DO NOT DARE REDEEM VOUCHERS, BUT USE THE APP, WHAT FOR THEN!!!!!

I have been scanning for a few months now and finally had enough points to redeem a voucher, BUT if you try and redeem any voucher they suddenly decline all your already scanned slips "After further investigation during your recent redeem, we rejected this receipt because it was found to have missing information or the image was unclear" But I have received errors when scanning, so how is it that when you want to redeem suddenly all is not correct with your slip. And you loose all your points only to start over. So the slogan is please scan your slip but do not dare redeem any vouchers we will reject all your slips.