I missed one of my online 7th sem exam due to technical issue in january, and now university says that I have to give this exam again, with next year student in December, 2022. I have been selected in 2-3 companies. How I can join them at time and clear my back paper later?

Question

My 7th sem exam were conducted online in January, in which 50 MCQ questions were asked and it was a one hour long exam. In which I have to login in the first 10 minute of exam. I live in village and here is no facility of WIFI, so I was giving my exam on mobile network. But that day for around 15-20 minutes network in our area disappeared just before the exam, and I missed that exam. I knew that I may need to face very big consequences because of it. So, I mailed university hundreds of time, and then they said, that it's normal if 10-15 students got a technical issue out of thousand students, you have to give the exam with next year in the month of December,2022.
I have been pretty serious about my education, and never got a back before. Even this time also, there was nothing at my end which I could have controlled. I have been selected in Infosys for Power Programmer profile and in TCS for Digital Profile.
What should I do so that I can join the company at time, and clear my paper in December, 2022?
I am really worried about all these from last 5 months.