Poor managing of client prove of purchase regardless if it is 12 months later

Last year february 2020 I made a purchase of a new wind screen which was on special for R650. 00 for my VW polo for an in house fitment. A month later in March Covid hit our county that forced level 5 complete shutdown, I couldn't bring my car for fitment. I recently came back on adjusted level 3 only to find out the BSG have relocated from Endenvale to Boksburg Jet park. Now they are telling me stories the person who captured my proof of purchase no longer works here and BSG can't find thier copy proving my purchase of R650. 00. A solution I have gave them is that a I have my slip as proof of purchase by law, If they cannot assist me they can refund my R650 in full OR they fit my windscreen as per agreement.