Internet going in and out

Is anybody else’s internet going in and out? I’m have this problem with Xfinity and this is happening way too consistently where I want to not have them as my internet provider anymore. This is so frustrating and ridiculous. I’ve called numerous times and the same “answer” I get it “we will send you a new modem” well no you won’t because it’s OLD modems. This one sounds like there are things loose in it? I know I’m not a “new customer” but you need to support you CURRENT CUSTOMERS. I unplug and reset everything and I get the same thing. I need help with this or I’ll be leaving.