Overcharged for M500 Broadband for 14 months!!

I have been charged £50.76  a month for M500 broadband since November 2024 which apparently includes a discount! Your M500 broadband only price was £33 per month. I'm also an O2 customer which is supposed to get a FREE upgrade to double my speed to Gig1. Gig1 pricing in November 2024 was £39.99. Can you explain why I've been charged £50.76 for Gig1 broadband as an O2 customer? Also why are you offering me the price of £58.88 to remain on the same M500 FREE upgrade volt Gig1  package when the price listed on your website is £26.99. I have been a VirginMedia/Blueyonder customer for nearly 20 years and find it disgusting that you abuse loyal customers in this way.