Originally Posted by london_chris

they will probably refund only the difference of what they should have cost you:

you buy 1 pair, at £150 and pay £75 for the 2nd pair,

they shoudl charge you 225 for each pair and if refunding 1 of the pairs you would get refunded the £75 and pay full price for the 1st half of the discounted pair of the 2nd set you purchase.