Poor customer service

Bought tether on Monday of this week during the 50% off sale. i did not receive the 24.00 dollar price, but the was charged regular 49.00 price. Wrote to customer service about this problem a man named Matthew wrote back saying "are system does not allow for half refunds" ...... Sorry but this i not my problem, i bought the item for the half off price, i rewrote today to customer service again today hopping to get this resolved. I am writing here today to see if this can be resovled by someone who has more power in the company, i view this as poor customer service if i am not refund the 50% amt. which i bought during your half off sale.....