It seems very odd that an add-on would be inadvertently added and paid for on your account. Why would someone do that? Can you give us some images of what you see? Don't show anything personal. Not your credit card. The payment history and your list of add-ons after clicking the little spinner refresh icon under the Shop Add-ons button. Does anyone else have access to your account? Is somebody else using the phone of that account?
Strange that the add-on in your account wasn’t purchased by you.
Could it be the free 2gb data and 200 minutes of LD calling that was the More is Merrier promo at the end of 2022 you are referring to?
If it is not this promo, only a CS_Agent can reverse the charges and remove the Add-on.
Just submit a ticket on SIMon Chatbot in the bottom of the page.