Scam vouchers are prevalent. If redeeming vouchers by means of coins, they will not show the capped amount (i.e. There's 10%off with min. spend 199, and then another but min. spend 1499,etc., they will show upto when the voucher is available, and what products it can be used on, BUT maximum/capped amount is not shown) only after exchanging the coins and looking at 'my vouchers' will the capped amount show up. Fix your app! Coins are non-refundable. Be clear and transparent with your rules!