Have to go in person to pay?

Hello! I’ve been an xfinity customer for a year now soon to be 2 in a few weeks and I’ve always been able to pay online but now all of a sudden I am not able to anymore. It says I have to go in person and the main issue with that is I live on a military base (I am currently active duty), I have no car so I am not able to even go to the In person store and it is also pretty decently far away! Which is really inconvenient nor fair to me. If there is a way to fix this so I could at least make a payment on the phone or through the mobile app again that would be really nice because I have no other choice otherwise.