Third party AT&T prepaid card extension
I purchased an AT&T prepaid card from Spain to a third party company called Holafly. The plan I paid included a service of 90 days. I'm going to be in the US for a few more days and asked them for an extension, but they told me they can't do that. Is there a way to extend it from the AT&T webpage when my subscription with the spanish company ends? I would like to keep my US phone number at least until I leave the country.
Thanks for your help!