Wrongfully charged, complete lack of customer service

My flat mate and I had our flat cleaned the DAY OF the inspection and the inspector even commented on how he is not used to seeing clean flats during inspection. The inspection took place on 11 December 2018 and we handed our keys back and have not had access to the flat since then.

On 25 January 2019 a Ms Julene Bonthuys sends us an invoice of R826.09 (deducted from our deposit without so much as warning us) for the cleaning of TILES! I am completely confused as to how we are held liable for the cleaning of the flat from after 11 December 2018 onward as Huurkor has the keys to the flat!?!?!?

DO NOT use this company as they will **** and lie to you every step of the way and even when you have done nothing but treat the property with respect, they will find a way to ***** you over completely as a final sayonara.

Oh also I have not received any feedback from Huurkor with regards to my issue since the day the invoice was sent so don't expect any form of customer service.