I want you cancel everything, but my landline

So I've had a few complaints about xfinity in the past few years. I haven't had voicemail for like 5 years. And they can't seem to fix that. No credits like promised, so they tell me to get a new phone. I buy a new phone, and now they can't. They can't activate that correctly. I want to give them the phone back and cancel everything. But my landline, i'm going to walk into the store and just put everything on the counter until i'm done.But how do I do that?If I still have this stupid phone they've pushed me in to get in promise, a year of free service which I never got