I've tried with them as well. Didn't work. But at this point I'm not sure how much of the problem is with the service, vs with Telegram trying to be really hard-core about not allowing these kinds of accounts. Seems like they're trying very hard to stop them.

With some of the numbers I've tried, I've gotten a "This number is blocked" message.

Looks like email is an option, though, at least with a phone sign-up. I may try that.

Though I have a hard time understanding why Telegram would allow email (can be pretty anonymous), but then not allow anon phone accounts.