Absured cost charged for storage affter repairs done.admin

I took my lawnmover in for repairs. After three weeks I was told that it was repaired and that I must collect it. I told them that I was not in Port Alfred and could not collect it. A week later I was send a invoice : Repairs R 600, storage R 500.00 I foud this to absured. Storage cost R 100.00 less than the actual cost for repairs !!