Bittrex complaint: Bittrex is preventimg me from withdrawimg my holdings

I opened my account with Bittrex 4 years ago. Recently I tried to access my account from another PC in another room in my house, and suddenly Bittrex asked me to complete Identity Verification before I could access my account. I have no objection to doing that, except that I tried and failed. I am 72 years old and I am not good with new technology. When I opened my account with Bittrex, I also opened accounts with several other exchange platforms, such as Binance, Coinbase, and others in Australia (where I live) and I completed their identity verification requirements, but Bittrex didn’t ask me for identity verification back then. Four years ago, completing identity verification was easy, I just uploaded photos of my driver’s licence and a selfie that I had saved on my computer. If Bittrex had asked me at that time, they would have used that method. But now Bittrex wants me to use my mobile phone or a webcam. (I have a webcam but I don’t have the code of the camera to install it on my computer. I am using a different computer now and unfortunately I didn’t keep the camera box which contains the code, and I really don’t need a camera.) My mobile phone is maybe too old to upload photos as required by Bittrex. I contacted Bittrex but the person who replied didn’t address the problem. I wrote again explaining my problem with the method they want me to use to submit photos of my ID and asked them to let me use the older method but Bittrex wasn’t flexible and now they won’t let me withdraw my holdingscoins. Since Bittrex allowed me to open an account 4 years ago, they at that time entered into a contract with me, ie opening my account and accepting my trades. I don’t see how they can now freeze my account so that I can’t withdraw my money or move my holdings to another platform. That is just plain theft. I have offered them a reasonable way to resolve the ID problem (not that I should have to do this after 4 years), but they are not willing to be reasonable, it seems. I would therefore appreciate your intervention to get this situation resolved so that I can access my account. Thank you very much.