Supply of Incorrect spark plugs

I sent my friend to their centre with a part number for spark plugs so to install in my 2002 Peugeot 206 1.6 16v and they provided me with the incorrect parts. Their spark plugs are way smaller than the ones my mechanic took out of my car. I though replacing the Dealer's Bosch spark plugs with the after-market Bosch from this service centre would be a better alternative, but I am now in trouble because I was under full impression that the items bought were correct and did not safe-keep the receipt, but I feel that those parts consultants at the service centre should not have provided me with the spark plugs if they were simply just guessing the alternative spark plugs.<br> <br> I ask to be fully refunded even though there is one package of the four provided open already. To also not to rule against me on the basis that my purchase was done more than 30 days ago. To also not to rule against as to not having proof of original receipt. You do keep records of purchases on your sales/orders systems I believe.<br> <br> I hope when the service centre receives this complain of mine, they are to ensure that their next customer is not disadvantaged as I am