@ Momo
I'd suggest you treat your capital expenditure in a similar way to a business (you are, in effect, "Momo domestic")
Keep ALL receipts and till-tickets, even if you just chuck them in a bag.
likewise all brochures, stickers, guarantees, tags from any "durable" goods purchased. IF a situation arises as above, you have the documented audit back to purchase-point.
You can argue till kingdom-come
The model only exists for two years. There is no possible way it can be out of the guarantee period
But what if they say "It's been on sale in West-Germany for 12 years" ???
I am
not saying you are dishonest but I've been there!
Customer wanted a full refund on a faulty item and was insistent this item was purchased at my store. I was adamant she was mistaken so she then threatened to take the matter to the local Trading-Standards office....I then quietly explained that we were obliged to do a complete stocktake every six months and that item had not appeared on our stock for over 18 months! I then pointed her in the direction of a competitor.
Set your stall out properly and almost every manufacturer will bend over backwards to keep you "on-side",,,stamping your foot and insisting you bought an item ay a specific place is NOT proof !
Jewellers have it sorted and make tiny code marks on most items.