Testing the limits of Shoppers Drug Mart customer service

I just returned from doing business at my local Shoppers Drug Mart. I had purchased something earlier in the day, for my wife, brought it home to her and turned away, as she reached into the bag, pulled out the receipt, tore it up, and then looked at the two items I had bought. She immediately informed me they were the wrong kind, to which I replied: "No problem...you've got the receipt, right?" She said: "Well yes, but I tore it all up"; to which I said: " You what?!?" Back to the store, with the hand-shredded receipt and the wrong merchandise, where I picked up two packages of the correct merchandise and headed to the check-out. Fortunately, no one lined up behind me so I wasn't about to delay or inconvenience anyone. Clutching my bag from the earlier visit, I set down the two correct items and said to the pleasant young cashier: "I'd like to buy these, please". I also quickly set down the two incorrect items and said: "...and I want to return these, which I bought by mistake earlier today".
"Yes, sir" she replied. " Do you have a sales receipt?" I said yes and opened my Shoppers Drug Mart bag for her to see the 20 tiny bits of paper. She immediately picked up her phone and said: "Supervisor to Cash 2 for a refund". Moments later, the supervisor arrived and the cashier says to her: "He would like to buy these two and return these two". The first thing the supervisor says is: "Does he have a receipt?" I piped up: " I certainly do", and opened my bag again to show the supervisor the 20 tiny bits of ravaged receipt.
"But it's all torn up...why did you do that?", she asked. I explained it happened before discovering the mistake about the wrong type of product , and that it was common practise, in our house, to tear up receipts for small, every-day purchases, as soon as we got home. I further explained that the receipts have our credit card number on them, and that one couldn't be too careful in this day and age of identity theft, etc., etc.
"I'll have to get my manager over here", said the supervisor. The supervisor started to explain to her manager and hadn't got very far when the manager asked: "Does he have a receipt?" There are now five customers lined up behind me, shuffling their feet and sighly loudly. I don't acknowledge them. Bad enough I'm wearing my floppy beret and looking like a wierdo anyway, without opening my mouth and saying something to the three guys in baseball caps and proving it.
The manager asks the supervisor if one of the tiny remnants of sales receipt has a transaction number on it. The supervisor replies one may, but that she doesn't know which one. The manager suggests that all three of them quickly examine the scraps, which they do, and a refund procedure begins. While I am filling out a form with much self-incriminating information, the cashier is swiping my credit card and my Shoppers Optimum points card several times and the manager is at another computer station producing an internal bookkeeping document. There are now seven people lined up behind me and the supervisor takes charge by gathering up all the detritus of this awkward affair and asks me to accompany her to another check-out, where we can be alone.
Mercifully, at no time has a discussion taken place about the actual product I'm buying: a laxative. I sign my name one last time and feel guilty because the two products I'm returning to the good folks at Shoppers are worth $45, and the two I am ultimately walking out with cost just $16.
Home once more, I now have two perfect receipts; a refund receipt and a purchase receipt, which I stare at momentarily. I notice that my credit card number reads as 12 asterisks plus four numbers. Well, I'll be damned! They don't print out your whole 16-digit credit card number. The two receipts sit beside me now, as I finish reflecting on this shopping adventure. I'm about to tear them up. Old habits die hard.
BtheB