I want to file a complaint

I have to contact xfinity mobile on multiple occasions to import a phone number, or my existing xfinity mobile account to the xfinity internet at my new address. Every call last 2-3 hours with transfers, and a request that I switch to another phone, although the phone I was speaking on did not require any service support. what can be done in the future to avoid the extended delays? This is xfinity and xfinity mobile.