Business btec unit 3 exam help

I need a quick response as my exams are coming up soon. Basically, I took my developing a marketing campaign unit 2 exam back in January, but there was an issue, and I was falsely accused of malpractice. I appealed, but nothing came of it. My teacher said I can either resit the exam next week or they'll consider my performance for the entire year. I'm leaning towards resitting the exam.
I also have my finance exam the week after, and I'm really worried that I'm going to fail. My teacher mentioned that if we fail Unit 3, we cant resit it and this we can't continue with this course but I'm unsure if this is true, please could you let me know if this is false?.
I'm most stressed about this because I don't know where l'll go if I fail and I have a chance I'm going to fail unfortunately, and I really want to achieve DDD or DDM.
Lastly, I'm wondering if my situation will put me at a disadvantage when applying to university. I really need some guidance as l'm feeling overwhelmed.