Sorry to hear of the issue.
The University will have a procedure if they allege misconduct on the part of a student.
There could be any number of outcomes from a reduced mark, a mark of zero (which is most common), having to re-take the exam , being refused the chance to resit, or even expulsion.
You will need to ask them why you have been accused of this - they will contact you shortly with any evidence they have and you will be given the chance to give your side of the story.
However, it would greatly help if you use a law firm (which specialises in academic misconduct) to speak to them and try to resolve this. If you don't then you are at a disadvantage and in the worst case scenario this could affect future employment prospects.
I will set out a few companies you could approach, as follows :
1. Click Here
2. Click Here
3. Click Here
Finally, please note that as an Internet forum (not a law firm), we cannot give legal advice - our remit is online information and guidance in a Q&A format.