Poor handling of issue

I am a member of the gym , Bodylab, since 2011 December, and I use their Witbank facility. I have never terminated my membership with Bodylab since I joined. In December 2016, they informed my that my account was in one month in arears. I checked records with them at the branch, and I paid the amount due, then, which was R174.00, using my debit card, and I paid right there and there. This, however, was never corrected in their records.

Since then, they keep on sending me messages and even told me they handed me over for collection. I sent them email time and again, but to no avail.