Purchase airtime online? | 7-Eleven Rates and Plans | Consumer forum

Does 7-Eleven/Speakout offer customers the ability to purchase airtime vouchers online? I'm trying to decide whether to go with Petro Canada or 7-Eleven.... there's more Petro Canada stations, so buying airtime won't be a hassle. However, there aren't so many 7-Eleven in the area so if you could purchase airtime online that would be a major plus.