Did these wipers really only cost £2 or is that more a rhetorical device - in which case the comparisons with the fuel cost of visiting the shop are a bit silly. Last time I looked it was about £25 for a pair of front wiper blades, so maybe 100 miles round trip equivalent in fuel?
To be frank, I misread the original post, I thought the wiper had been used for 9 months and you were trying to return it.
so ill retract my "hhahahahahah" and say that id probably agree that if its in its packaging then I would have expected them to swap it for the right one... I mean what does a wiper blade cost. If it had been opened then I wouldnt expect anything.
I had a similar situation recently where I was trying to be organised and looking around for a decent set of leads for my 500SL. I knew that I didnt need them until November but I know I face issues getting decent quality leads for this model. I change leads on all my cars every 3-4 years.
So in April I ordered the set from KMS parts in Birmingham.
They delivered them and i Paid the £120 for genuine Bosch items that looked proper OEM.
November comes and im under the bonnet only to find they have the wrong connections on the distributor cap end.
I ring KMS and they arent interested and tell me that my car has the wrong cap! Despite me getting the correct leads from them 4 years prior and all of my other V8's having the exact same setup.
So Im now stuck with £120 leads that I have no idea what they will fit and ive had to order the right leads from Magnecor... Thankfully once they are installed I will never have to worry about the leads again as they are made properly.