Amazon's tech support number is 1 (888) 283-1829 https://www.amazon.com/gp/help/customer/display.html?nodeId=202101470UPDATE:
So I called YT again to cancel my account. Their number is 855-276-3666 and shows up in internet searches as YT support and Amazon support. It's some call center somewhere. The people on the phone have strong eastern accents and are hard to understand.
As far as I know, there is no possible way to contact YouTube via phone unless you are a big shot and have contacts working there.