Hidden debits to be watch out for.

Placed a "free ad" with them, but sold the item locally in my private capacity. After the sale I deleted the item from their website. Upon deleting the item they claimed a listing cost of -R50 debited to my account, when I enquired about the amount I was informed that I enhanced the advert. Why would I enhance an advert if 1. There is no money in my bidorbuy account and 2. Why would I enhance something if I sold it? Watch out for this lot!