Slack Accounts Department!

I gave notice to Blue Hawks that I was moving, contacted the sales rep and my contract was taken over by the new owner of the house. The accounts department was informed by the sales rep but my account has now been debited two months in a row despite having ticked all the boxes. I have contacted the sales rep and was told that the accounts department would contact me but the silence is deafening. This is incompetence at it's best!