In general, if the customer does not pay in time after placing an order, you can remind the customer that if there are any problems with the price, size, etc. of the product, you can inform them in time, and you can also remind the customer that the product will be shipped as soon as possible after payment.
Dear customer,
We have got your order of ***. But it seems that the order is still unpaid. If there’s anything I can help with the price, size, etc., please feel free to contact me.
Once the payment is confirmed, I will process the order and ship it out as soon as possible.
Thanks!
Best Regards
(Your name)