xfinity blocking SIP traffic in gateway

i have a grandstream HT802 adapter to use with a 3rd part voip provider and ported my xfinity number to it.

it was work fine for several weeks so i then cancelled the viop  service from xfinity.

at that point the the adapter stopped working and i am no longer able to make or receive calls

that fact that it worked until i cancelled the service suggests that xfinity is explicitly blocking this traffic once i stopped paying them for the service.

is that the case and is there a way to have them not do so?

(i enabled port forwarding as suggested by the voip provider but that did not help.

this forum suggests turning on bridge mode but i have wifi extenders so don't want to do that.

the viop provider also suggested modifying the SIP ALG setting but there seems to be no way to do that,

i also tried disabling the firewall.)

is there a way to get xfinity not to block SIP traffic?