you should be ok, as the statement refers only to ill-fitting clothes rather than damaged goods. alternatively if they won't give a refund, you should be able to exchange the jeans for an undamaged pair.
Yes, i work in retail and as long as you keep calm and explain what happened they shoudl should offer you a refund as their product is at fault.
If they offer you another product instead say you were already disappointed when u got home and dont want it to happen again so would prefer a refund.
If they still persist, ask for the manager, or then say you will take this further. They last thing they want is to get area management involved! Remember the customer is always right!
It puzzles me when shop assistants say they don't give refunds, although it's only ever happened in a couple of shops. I'd always assumed that your statutory rights are set by law, and an individual retailer has no power to amend them. If the goods are faulty, you're entitled to a refund - they have no right to refuse.
If you have a look at the TRADING STANDARDS website (not sure of the address - just Google it). You are entitled to a refund if the item you buy is faulty - Even if the shop says you are not. That is law. Just take them back as soon as you can and if they won't give you one, contact Trading Standards or at least threaten them with it. Make sure you have read up on your rights though first so you sound like you know what you are talking about.
I should point out that if you bought them in the sale and they pointed out that the button was loose, this is probably not the case as thats how you bought them.
The law is that if goods are faulty, not fit for the purpose, or misdescribed, you are entitled to a refund. Retailers do not have to give you a refund if something dosnt fit or you simply change your mind, in fact they dont have to do anything for you in these circumstances. So retailers that offer you an exchange, credit note or vouchers, are doing more by way of a returns policy, than they legally have to, hope this helps.