Account debited even though settlement amount paid

Wednesday night on the 14th of February I went online to the Wesbank website and requested a settlement letter. I received the letter the following morning 15th February informing me what the settlement amount was and I went to FNB that same day to deposit the settlement amount. To my surprise my account was debited of the monthly installment on Friday morning the 16th February, even though the car was settled. I went online and logged a call on the Wesbank website sent through the settlement letter copy and the proof of payment with this reference number; 253961. I did not hear anything from Wesbank after that. So I called through to your contact centre this morning to query this and the lady who took my call refused to assist me without the account holder who is my husband even though I informed her that the money is debited from my account monthly and I can confirm any security details she needs. This is really frustrating as other accounts I needed to pay bounced cause of insufficient funds on my account due to your company's mistake and I'm still not getting anything straight to inform me when my money will be paid back.