Very Bad

I had a contract with gym company for 3 years which ended on the 30/06/2019. My debt order was on the 27 every month. In the month of June we had problem at my work place we didn't get paid on the 27th of June which was supposed to be my last payment, but however I paid the due amount on the 27th of July. Through out these 3 years I didn't receive any communication from Gym company even on the month of June when they did not receive the payment, but because I knew that my contract is for the period of 3 years I paid them on 27th of July 2019 to finish of my 3 years contract . On 12/08/2019 I received an what's app chat from Palese from Gym company(Bara) saying my account is due for payment, I asked her what is she talking about because my contract has ended and I paid 3 years in full even though I only attended the gym less than 3 times . She said I must cancel the ended contract. I told her that I do not understand what she it means and I wont pay for something that I do not understand, then I told her that I want to cancel then she said no you are on arrears I asked her what arrears because I paid 3 years contract in full ? I made follow up on the 15/08/2019 this time I found a different consult, I asked her to escalate the matter to her manager, she said her manager by the name of Lesego will call me today I waited the whole day today but she did not call me. Where can I be assisted with this mater ?