Tracking and returning unauthorised debit

I called the bank and asked for a reversal or for an unauthorised debit to be returned as I do not know the vender nor did I authorise the debit. I was advised it will take up to 40 days for the matter to be resolved but what I’m trying to understand is the bank going to wait for the 40th day for that query to be attended to cause that disheartening that my bank where I put in money and create business for, doesn’t even give feedback as to this is where we are with your enquiry and every time I follow up nothing has been done since 2 weeks ago, will it ever be attended to taking into account I’ll be charged for the money to be returned and my bank allowed a debit to go off without me granting auth like all the other debits which need to be approved first