If your customer has not received the paylink you sent, chances the email may have ended up in their "Spam" folder, there may have been a typo when you entered the email address, or the customer could simply have given you the wrong address.
The first thing to do is ask your customer to check their spam folder for the email. If they still can't seem to find it, you will need to resend the paylink by going through the exact same steps as the first time you sent the paylink. However, before you do, ask your customer to confirm the email address they wish for you to send the paylink to. Once they've confirmed, double check the email with what you have saved for your customer and make sure they match.
If everything looks correct, and the paylink still fails to arrive please get in touch with our support team so we can look further into the issue and aim to resolve.