Any country any number is fine. They don't accept VOIP, Textfree etc kind of numbers so anything other than that should work.
is this a one time verification or you need the number active/available for a long period or future
also, if you hesitate paying in BTC because its significant fee
you might offer other altcoins... I'll take doge or ltc... doge is quite cheap on tx fee
if you use/have balance on exchanger you could do it from there, exchange then send away
any exchanger usually have basic trade pair btc, doge, ltc (and eth recently)