We have been using this store for years and must h...

We have been using this store for years and must have spent thousands there. One week I walked in as normal and tried to find the correct pumping fitting at this point I noticed a store employee sneaking around and watching me. At the time I didn't take much notice as I wasn't having much luck plus a have a long and boring phone call from a client but I kept seeing the same employee walking past the aisle trying to look natural and inconspicuous. About 20 minutes later I was at the checkout paying when I spotted him again lurking by the exit. And when I went outside this security guard stopped me and requested I accompany him to the office as I had nothing to hide I did. After emptying my shopping bags and pockets in front of the security guard and he apologising for the inconvenience I walked out but at this point I heard that same sneaky staff members state quite loudly in front of other customers "he must've dumped before the checkout" . This is when I stopped turned around and asked him what is he saying and implying. "I saw you putting stuff in your pockets" he replied even louder than before. Customers and checkout staff stopped what ever they where doing and started to observe The situation. I did my best to reply in a calm and collective manner but I did lose it and "before you accuse customers of stealing make sure you're right and if you're not apologise pretty f***ing quickly and hope they accept your apologies" he replied "I'm not apologising for doing me job" this is when I walked out. I sent a complaint email about this event but got a standard reply. Thanks B&Q