Our entire class has been screwed over by Pearson and our teachers

You need to take this up with the college head, first call. The college need to appeal the decision by Pearson and sort this out. Try and secure the support of a parent if you can.

If the Pearson decision stands it could affect your end grade, Not sure how specifically biomed is graded but typically you are allowed i think to slip one grade in a unit but still hold the D* end grade. So if it was an extended diploma for example with 13 units, and 12 were at D and one at Merit you would still likely get the 3 D* end result. So i suspect you will be OK.

In all, this total balls up by the college may not end up with that greater impact on you BUT even so you want and deserve the right result to give you the best chance when you apply.

Good luck

Hi, I'm currently attending a BTEC biomedical/forensics course and I've encountered a problem that I believe was no fault of my own. To sum up what's going on, my assignments, which have been internally reviewed and marked by my teacher, and then externally reviewed by another, have just been sent off to Pearson to be externally reviewed by them. Anyone who got the distinction, in A-level terms that's an A) has just been informed that every single person in our class is missing something from the distinction criteria even though it wasn't on there (yes our teachers confirmed that it was not part of the criteria). The 2 teachers who had marked our assignments, gave us the distinction mark, not telling us in any way that we had been missing this from our assignments and telling us that we didn't need to resubmit our assignment to achieve that grade because we had already achieved it. Feeling guilty about this they requested to Pearson that we be allowed to resubmit this one final time. They were rejected. I don't understand what went wrong, between us being given an assignment brief with missing criteria, to teachers failing to properly review and mark our assignments, or Pearson marking our assignments with different criteria. This feels totally unfair and unjustified that we aren't allowed to resub this assignment, leaving almost 90% of the class (me included) feeling that we may have to retake the year because we may not be able to get into any good universities with our grades. My teachers/classmates had suspicions that Pearson has hired someone who doesn't know how to review/mark assignments since the 3 assignments reviewed by them so far, no one has managed to achieve a grade suitable for a distinction (for clarification we have about 20-25 people in our class and about 15-16 of them got distinctions meaning that over 45 assignments marked as a distinction have been dropped down to a merit). I want to appeal this but I've looked at the appeal process and I may not be able to afford it. Does anyone know what to do?

Firstly, someone (teacher?) is giving you incorrect information as this is not how the process works (I am a Standards verifier Team leader for Pearson, but not for Science so I will explain the process below) and Pearson certainly dont want to disadvantage any learners, so dont 'screw you over'.
Secondly. getting a Merit instead of a distinction for one unit will not affect your overall grade too much, so it wont affect University applications.
Thirdly, Pearson do not hire people who dont know how to mark, as all Standards verifiers are subject specialists (current and retired teachers).
Fourthly, there is no cost to appeal internal marked assignment issues (they only charge for Exams appeals).
Link to Complaints page; https://qualifications.pearson.com/en/contact-us/students.html?level1=File%20a%20complaint
but you need to use the Centre complaints process first before contacting Pearson.
I have put a link to the specification below, and this is what teachers and Pearson verifiers use to confirm if learners have a Pass, Merit or Distinction for each unit. Additionally if your school / college is using the Authorised assignment briefs, then there can be nothing missing from the questions.
Pearson ask schools to send work from three learners for up to three units, so a maximum of nine. If each unit has three assignments, they are checking 27 pieces of work.
You dont say which unit/s are affected, but in the specification you will see that for every unit, there are a couple of pages titled Essential information for assessment decisions. This in addition to the assessment criteria, is what the Verifier goes by to check each assignment.
Have a read for the units affected and see if you and your peers have done this.
If the Pearson verifier disagrees with the teachers marks (which is the case here), the Centre is given feedback and all of the learners should redo the work and make the corrections. This is then sent off again and if the Verifier agrees the changes are sufficient. then the Distinctions would be approved.
https://qualifications.pearson.com/content/dam/pdf/BTEC-Nationals/Applied-Science/2016/specification-and-sample-assessments/BTEC-L3-Nat-ExtDip-in-Applied-Science-Spec.pdf

Apologies for my rude behaviour, after having just learned this yesterday it seems i've let my emotions get the better of me. However, our teachers have been told by Pearson that we aren't allowed to redo our assignments. Also, the centre that supplied the feedback said that no one achieved the grade 'distinction', and my worries are that when our other assignments are sent off, there's the possibility that this may happen with other units.