Illegitimate deductions on deposits!!

When we were supposed to move into on their flats on 1 May 2017, their previous tenants have not yet vacated the premises. The agent did absolutely nothing to speed up the process, she left and told me to phone her when we have moved in. Neither the outgoing inspection, nor our ingoing inspection was done in an empty flat, Both was done with furniture still inside the flat, therefore they are unable to determine who caused which damages. When we moved out on 31 March 2018, our outgoing inspection was done in an empty flat and I was told the unit had to be painted out and the owner would be responsible for the costs. Upon further investigation as to why my deposit has not yet been paid out, I was sent a quote for 50% charge of painting out the unit. (This quote was for R1650 and specifically mentioned that it includes callout and labour) This was due the fact that my TV bracket had to be removed and I was therefore liable for painting that specific wall. The quote was issued on 1 April, but they only heard on 16 April that the new tenants will not be using the bracket and it has to be removed. How can they know on 1 April to charge me for damages that they only became aware of on 16 April? Furthermore, when I showed them on the mistake in their calculation and how on earth they could charge me for 50% if I was only liable for one wall, the amount changed to R1000 with still no explanation of how it was calculated. I phoned Nadia again to ask how this was calculated and I was told that they charge R4400 for painting a two bedroom flat and the painters had to go back again, because they could not finish their job in one day. I was charged for one callout and the owner of the unit, was charged for the other callout fee. Now my questions are: 1. If you have a set tariff of R4400 for painting a two bedroom flat, why was the initial quote for only R3300 (R1650 x 2)? 2. This was not a "per day" tariff, so if the painters had to go back a second time, it is not the client's responsibility to pay another callout and labour fee. 3. How can one wall in a unit with 16 walls, amount to 10% of the damages? I asked these questions on 25 April 2018 already, and to date, I have had NO response from anyone at SAIR. The agent have no calculations to substantiate their deductions and their lack of proving their calculations and answering my questions, supports my belief that the deductions on my deposit was illegitimate.