Discounts on rental

Good day, I hope you are well. I have a query that I would like to address, I am a tenant of afcho properties, and I have been in one of their property units for just over 12 months now, they have been sending communication that on your 7th month you will get 25% discount on your rent, but I have never gotten any discount so today I sent an email to them asking about the discount, only today they tell me that the mail was sent by error and it only applies to tenants in the inner city of Johannesburg. I am very frustrated because it's not the first time something like this happens , and our rent was also increased without any communication, I need advice from anyone to assist because this is no way to treat a tenant. I mean now I have budgeted the rental for the month exc the 25% that was promised to me in writing, who should now be held responsible for the remaining amount, I see this as false advertising and very inconvenient for the tetants. This is just bad bad customer service at its best. Lerato