Ghost charges!! Out of the Blue Costs!

I have never missed any rental from the moment I moved in with Ithemba. Last month I took a transfer to different from Purchase Place to Brostoringof, before I moved they sent a bill with the cost of the transfer process, the new rental amount, lease fee, top up deposit, and everything else, I paid all that. To my surprise when the bill for this month came there is an arrears/balance bf amount of R2190.00. When I contacted them via email the agent said there is an issue with the documentation from the previous Purchase Place, they will update me. On that same day I received another invoice for the previous apartment that I transferred out of, Purchase Place. Which meant now I have to invoices for different apartments, Now I have received a letter that says according to their records I have failed to settle the amount and I must pay or make arrangement. I can't pay for arrears when I have never missed any payments and not even aware what the arrears is for. Where is this amount coming from.