Problems Purchasing a Plan

I have owned a Ring Doorbell for seven years having purchased it from Amazon UK and was hoping to buy a Ring Plan so that I can view recordings that have been made. But no matter what payment card I use I get a message so 'oops something went wrong, try again later'. I have tried many times and get the same message every time.I phoned customer support and spoke to two people who said they could help me. But they failed. The second guy I spoke to seems to think the problem is caused by not having the doorbell directly from Ring.Amazon do not offer a way of buying a plan.Has anybody else experienced this issue? Does anybody know of a solution?