Repeatedly Shortchanged on Refunds after Overpaying

Despite renewing ahead of our contract ending and assurances from reps that it has been corrected, we're billed a non-contracted rate for one month every year we renew our internet plan.  Our bills are paid by autopay, but if we remove it as reps advised, we lose our discount the following month, even if we reinitiate it soon after the bill is paid.  Every year, we have to ask for our money back, and we're shortchanged about $5 from our refund.  

This year's renewal took several chats and calls because the rep handling our renewal never put in the order, and we're later told from their loyalty dept that their offer to keep our previous year's rate was a "mistake."  It will cost us more to keep the same plan this year.  We were refunded for overpaying but shortchanged again.  

Appreciate if someone could resolve or explain the shortchange by written correspondence, as some reps don't have access to refer back to previous communications.