Invalid garnishment

In 2016 I saw a deduction on my salary advice with reference of Gerhard vd Merwe of R500.

I asked at work to clarify, and I was told it was garnishments. I contacted them and asked for the order. They sent me that order and I knew the creditor but nothing about application for garnishments against me.

As far as I know, I have to be informed and be present in court to present my side, I was not offered that opportunity. This makes invalidate the order they used.

The rule is, the order my be obtained where the defendant works. The order was granted in Mthatha, Eastern Cape; by that time I wasn't working in Mthatha, but I was working at Mafikeng, North West. This make the order invalid.

All I want now is for them to pay back my money.