Unfair and possibly ******* business practices

We have a rental agreement with AFHCO, and we are based in Lifestyle Estates, South Hills, unit 209 block O. According to the rental agreement I am supposed to pay R4995 per month. On the first of July I made a payment of R5000 into AFHCO's account. As you can see that amount covers the rent. On Thursday 11th of July 2019 I received a letter of demand that says I am owing R247.51. it further states that if this amount is not paid by the first of July (two week ago) then I will be listed. For starters this letter does not make sense and secondly I was not contacted earlier about this issue before I received this letter. One other issue, I reported maintenance related issue which is bathroom tiles that do not have grout and could crack anytime. This poses and an additional risk since we have two kids in the house. This issue was reported in Jan or Feb this year but still today the issue is not resolved. If feel this is an unfair practice that needs to be highlighted escalated if possible. I am also planning to take this matter to the rental tribunal for further investigation. The AFHCO account number is 48952.