switching xfinity sim from broke phone to new phone with past due balance but was given an extension. Can I do it without xfinity support

My phone recently got wet and the touch screen quit working. I bought a compatible moto g off amazon and was given a extension by xfinity mobile on my bill. when I tried to go through support they said I now had to catch up my bill before I could switch to my new phone. can I safely just switch the sim into the new phone without using xfinity support?