Verizon review: Unauthorized charge

Verizon is charging me an additional $40.00 for the month of April because they state my loyalty reward has expired but i have no documentation of this. I have been with them for 8 years and this is the first time I am up against this. They want to charge me $ 184.55 for the upcoming invoice by auto pay, but they will reduce my payment to
$ 140.53 going forward. However ,I refuse to pay the $ 40.00 for the current month as I believe it is not legal.
Please provide the written notice, plan terms, and account history showing why my loyalty reward expired and why a $40 charge was added for April. I dispute this charge and request that Verizon remove it and restore my prior billing amount.”