Great thread!
Another one here who used to buy a lot more clothes from M&S for all the family than I do now.
I've stopped buying jeans and trousers from them almost altogether - I used to live in the Roma Per Una cut jeans but these days find that Sainsburys jeans are about half the price and if you buy their Roma equivalent (think it's called something like classic waist) then they are even better cut and last just as long... I've had far more compliments wearing Sainsburys jeans than I ever did wearing M&S ones which really surprised me. I've also found that the Sainsburys tshirts and tops are often much better too.
I've just been caught out on the online returns - and it's partly my own fault for not reading the form it came with really carefully - because it is there in black and white. But - in my defence - M&S have always had an extended returns policy for things bought in the run up to christmas - so even if you buy something in mid november, it can still be taken back up to a couple of weeks into the new year (usually about the saturday closest to being two weeks after new year's day). I just assumed that policy would also apply to stuff bought online - because you can still take it back into store until that date apparently - just that you can't send it back outside the 35 day time frame. Unfortunately I had lots going on in December/early Jan which is why I hadn't clocked the difference - I knew the extended date as a nice M&S person had reminded me about 'anything you get from M&S now (ie november onwards) you have until Jan 16th to take back and get a refund' - so by the time I'd read the letter it was already beyond the 35 day limit, but inside the other limit and I'd just assumed that they had a standard printed letter for online deliveries but that the extended xmas date would also apply but they didn't change their stationery specially. Hey ho. learn an expensive lesson!
So I now have a cashmere jumper (half price on black friday) in a colour that doesn't look great on me and some uncomfortable pyjamas that are a yucky colour that doesn't look the same as it did on the photo that got sent back to me along with a snotty letter. 