Hidden costs and December rent

I was staying at Festivals edge which is owned by MidCity. At the beginning of the year, we were told that they take NSFAS students and we wouldn’t have problems, in March after I signed the lease, I was told that I have to pay R500 extra with is hidden costs. Now I am told that I owe money for December rent whereas NSFAS pays up to November. I cancelled my lease in November and moved out yet I am still held liable for December rent. I am unable to pay for that rent because I am fully dependent on NSFAS. I was **** to just so I can sign the lease, they said NSFAS covers all costs yet they still have hidden costs which NSFAS does not pay for. I have paid R4000 out of R5000 for hidden costs which include water and WiFi. They are threatening to blacklist my surer