Not willing to assist

Went to the Signet Terrace Lenasia branch and bought a JOJO tank. I was informed to go to the side of the store and collect. After borrowing a bakkie I went to collect and was told that the tanks are not in stock (waiting period 7 days). I agreed to wait. 2 days later they called me and informed me that the tank has arrived and is ready for collection. I searched for the pick up slip and realized it is misplaced. Went to collect and explained to the dispatch that I do not have the slip and was told to go to the management office to sort out. At the management office I was attended to by one of the owners who refused to assist me and had a bad attitude. No slip no tank. I offered to show him my banking app that confirms the payment by dr card but to no avail. I informed him that he should keep my money (R 2200) as charity as it appears that they are in dire need of it and left the premises.