一般情况下，客户下单后没有及时付款，可以提醒客户若有产品的价格、尺寸等相关问题，可以及时告知，还可以提醒客户付款后会尽快发货。

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)