use of cell phone number for verification

I am the primary user on my xfinity account, and am no longer capable of using my cell phone (it is currently de-activated); I want to change the cell number to my husband's cell phone (he is already on the account as a manager, and he has the app on his cell phone), but the system won't let me switch it because his cell is already associated with the account.  I can't change anything in my account (such as change primary user or even transfer account to his name) without verifying who I am by using the cell number I can no longer use.