Shocking changes to my account with no information ever given to me or signoff!!

I have had an Edgars account over 20 years and in the last 2 years my payments are not reducing my balance....I finally got my 1st statement in January 2025 and see that since at least 2022 Jet purchases have been put onto a 24 month payment plan at 21% Interest. HOW CAN YOU DO THIS WITHOUT INFORMING ME!! I am horrified to know that I have been paying for the last 2 years and not reduced my balance due to the horrific payment structure imposed on my with the changes made. I called and asked for assistance to understand and change these purchases only to be put on hold and then hung-up on when I finally got hold of someone at RCS accounts.