FNB upgrades you to an account with higher fees without your permission and then wants you to pay bank charges for trying to fix the account

fnb went and upgraded my account to a private clients account without my permission and I noticed the high bank charges, this month, as I dont expect to be upgraded without my permission, and now that I want to fix the account and downgrade it to what it was before I am told that I am responsible for the bank charges, and then they still lie and say that I said that I have upgraded it in error, I am getting really sick of FNB and all its ****, the homeloans department treated me very bad, and now I must deal with my cheque account ******* also, you upgraded me and now I am responsible for charges and pro rata charges, I told you the reason that I am downgrading from private clients to begin with is that I see now value, and then I downgraded the account, just for you to go and upgrade me again, without my permission