This is unfortunate. Sometimes a new, better mitcirc application will be accepted even when an initial claim was not. Homelessness/living accom issues can count toward MC claims, and so it is worth speaking to the right people and getting some advice on this.
You really need to speak to an academic advisor and/or somebody involved with exam board decisions (usually professorial staff or heads and deputy heads of department). Do this as a matter of priority. The SU might have some guidance on this too.
Revtransport strikes (and for the benefit of others):
What you should do in such circumstances is apply for mitigation citing every possible reason, and then sit the exam anyway. This allows the exam board to apply appropriate mitigation after the fact.
Saying that you didn't sit an exam because you were not well prepared does not bode well even in the light of other circumstances. The onus is on you to know about strikes being on or being cancelled, and it is your responsibility to make appropriate arrangements. It is not the University's job to do either of these things. The strikes being cancelled effectively nullifies the initial MC offer from the university and means that you ought to have sat the exam. The MC team will have taken all this to mean that whilst the circumstances are not ideal, you could have mitigated them yourself. This being the case, they will not be minded to mitigate them for you.
Overall your housing situation might have legs, but it depends on the specifics. You need to push this by speaking to the relevant people ASAP.
Transparency: I'm not a student rep, I am an academic who specialises in academic advising, procedural claims, and student support at a top UK institution.