My usual Sainsbury's. August this year. Bought a £6 box of Belgian chocolates (which were displayed upended, if that makes sense). Opened them the following night to find they had all melted and the fillings had poured out everywhere.
Took them back a couple of days later. First woman at customer service desk cheerfully says "it's a good thing they weren't a gift!" and tells me to get another box.
I return with replacement box; she's not there but a colleague is. I explain what's happened and to my amazement this colleague tells me I must have stored them somewhere warm and that's why they've melted. She repeats this several times. Flabbergasted, I tell her I live in a cold house. Eventually she gives me the chocolates but in the most sneering, unpleasant way.
I go off to get a basket to continue my shopping, and walk past this snotty bitch slagging me off to a couple of other colleagues. I couldn't quite believe what I was hearing. I would understand it if I was a regular piss-taker at the customer services desk, but this was the first time I had ever returned anything, I was polite and friendly and it was a fucking £6 box of chocolates.
I emailed Sainsbury's customer services to complain, got an automated response saying "we'll reply in three days!" and have heard nothing since. I haven't been back to that store.
Ironically, the weekend that this happened, we had gale-force winds and relentless rain (standard Cornish August). There was absolutely no way those chocolates could have been sat in the sun and melted BECAUSE THERE WASN'T ANY SUN.
Stupid bitch. It still makes me angry now. At least the (non-melted) chocolates were tasty but I kind of wish they'd also been melted just so I could go back and wipe the nasty sneer off her face.