Unauthorised debit

I downgraded membership from premier to one club alone. I was assured that the correct fee would be deducted since I performed everything in time for this. Yet, more than DOUBLE of what I should have paid was subtracted. This is terrifying - I am a full-time student surviving off of study grants. I need this money back asap. Please contact me and I will forward relevant communications. Please also be advised that phone calls are difficult for me on account of being in the library all day.