Overcharge on bill

I had a $160 increase on this months bill and Verizon customer service can only explain $15 of it. I have ten lines, so this overcharge brings my bill to over $680. When I call customer service, I’m routed to a call center in Ireland that can’t see bill pdf and can’t receive emails or texts so they only offer a $25 goodwill credit. The supervisor told me to go to a retail store and she would memo the account telling them to credit me. Of course they wouldn’t, that’s an issue for customer care. 
My question:

how do I get to a rep that can actually assist me? At this point it looks like I’m going to have to eat the charge and switch to T-Mobile. 
I’ve been with Verizon almost ten years and have paid over $30k lifetime with zero credits. This is ridiculous.