[anonypla]

Writer of the guide here. I actually do tell you what to do in that case:

- Take the cost and go physically to such a country

- Use online services such as dtmf.io and pay with Monero (there are others but I didn't test them and some are "sketchy" to say the least)

But you could also just ask someone you trust in such a country to buy one for you (carefully) and mail it to you including a top-up voucher paid by cash.

Otherwise well just don't use services that require phone numbers for verification. No other way I'm afraid.