Registration

I've been accepted to ITU and planning to join it this year. I'm trying to register but it says it should be done in-person which is virtually impossible since I'm an international applicant with no visa yet, which in turn is because ITU hasn't given me any acceptance letter or such. Just an admission code which is supposed to be used in the visa process, but when I take it to visa application centres, it's turned down because they want the letter and they don't know what to do anything with this. When you email the office to ask about this issue, they don't respond, it's been 7 days since I emailed them first but no response to that. Countless other follow-ups but nothing came out of it too. What the hell am I supposed to do with the code? Where should I put it? I have turned down every other institute for ITU and this is my last straw. Not sure what to do now. If anyone knows what should be done, please help me out.