Service agreement price not honored

My service order Confirmation dated 12/07/2023 stated " $90.00 per month for 12 months, then $12.00 per month for 12 months 13-122. Current regular rates are $112.00 per month." Internet/Voice Equipment Rental $15.00/mo  Taxes, Surcharges & Fees $0.90/mo Autopay & Paperless discount $5.00/mo  Xfinity residential monthly total $100.90. This is what I paid for the first 12 months. My bill is now $123.90.  This agreement can be interpreted 2 ways for the price increase after 12 months.  It could be $90.00 plus $12.00 = 102.00 and after adding $15.00 for equipment rental and $0.90 for taxes and subtracting $5.00 for autopay discount, the total would be $112.90.  Another interpretation would be $12.00 plus $15.00 for equipment rental and $0.90 for taxes minus $5.00 for autopay discount for a total of $22.90.

There is no interpretation that arrives at $123.90. I would like an explanation of how my bill increased to $123.90.  I am also curious to know if my bill will stay the same for the next 9 years as stated in the agreement