Horrible service

I upgraded my phone with them in 2017 I've always had insurance with them they do the quote the monies are included in my payments i don't even pay separately now i have an issue with the upgraded phone I'm told I'm under insured..how when I've been paying since the inception of the phones all the upgrades are done by them now I'm being told they can't fix my phone. The you speak to a consultant for a solution she is telling you she doesn't know what to say so who must know? I am so upset and disappointed with their service and how they treat their customers