.... its a charge not a product/ service.
and your not supposed to go over your limit hence unauthorised.
I got charged £30 because the bank took 0.40p in interest from the account when I wasnt using it. and then another £30 the next month because I hadnt paid it off. £60 for 40p interest? no thanks.
Of course it's a charge. That's how products and services work - the bank supplies it and charges you a fee to carry out that service.
If your bank was sensible they will have written to you telling you that they were going to take interest. My bank write to me every month telling me how much my overdraft is going to cost, and exactly when they're going to take it out. Again, if you think a service is too expensive, then why are you using it?
because of the way the contracts are written and the fact they are fining you for going over. £30 is not an admin fee which is reasonable.
The terms and conditions for my account use the terminology "service charge", which is exactly the same as "charging for a service".