Overcharged due to closed offices

My last day to move out from Kempton Place B727 was on the 01 December 2017 at 12:00. I was packed and ready to go when I went to their offices and saw that there was a notice stating that they will reopen on the 2nd December. I left with the keys knowing very well that I would return the following day for the inspection. I was surprised to be contacted by Reuben their maintenance guy,who told me that I would be charged for late moving and for occupying a flat that now belonged to someone else. I explained to him that I went to their offices and they were closed and that only the security guards were working. He told me that if I wanted to find the other staff I could have made a plan. I find this very offensive and rude from City Property, especially since I have been their tenant for over a year. I tried to call Reuben to tell him that I can come on Saturday,he told me they would charge me R1000 for late moving. City Property and their staff seem to only care about making money, how am I to be blamed for them closing their offices. If this matter is not resolved,I will consult Legal Wise for a legal opinion and I will go to every social media platform.