Please help! I have ZenCat 3.7.1 and have just set up my online shop using PayPal but my customers are having trouble paying! If they select to pay without a PayPal account and fill in their payment details, once they select to submit the payment doesn't seem to go through and they are asked if they want to 'Retry'. If they select this it says they may be charged twice but still doesn't work! I receive no order or payment so neither have obviously gone through. Does anybody know why?! I have a PayPal business account. and have downloaded the Express Checkout but nothing seems to work!