The only reputable service that I managed to find was CoinGate. KYC is required though, and not all countries are supported. This is the list (assuming that nothing has changed since 2018):
For the first turn, we have introduced buying Bitcoin with Mobile Credit in 19 countries: Austria, Australia, Belgium, Canada, Cyprus, Czech Republic, Finland, France, Greece, Hungary, Ireland, Israel, Luxembourg, Norway, Poland, Slovakia, Sweden, Switzerland, and United Kingdom.
The page they posted is redirecting to
https://coingate.com/trade but nothing is showing there. It might be better for you to create an account or contact the support (if you're not from the above countries)