Inaccurate billing and legal threats

During the renovations at Villa Alba complex in Centurion in 2014, a member of body cooperated targeted property owners individually enticing them to an enactment of a stoep which initially was going to require just R1500 on top of what was the agreed upon renovation fee. I greed to this, as I thought it is reasonable. However at the end of the project she indicated that the stoep would cost R6000 and later on Kibo indicated that it was R7000. I kept asking how it could change but instead of a response their lawyers started making demands. I made payments which exceeded R7000 due to their inaccurate statements they kept sending me. But I was shocked to continue to receive demand letters from their lawyers stating I only paid only about R3000 in August. I sent Kibo emails, and payment proof despite all that, I still receive letters of demand from their lawyers. I really need these people off my back, it's bad enough that they poorly run our complex , they should not add ******ion of money to their already bad reputation.