文法是否正確? 明白全剖meaning嗎?

For a few customers who live distant places, online and mail is more convenient to them. For online application, they can send application form through internet, after that we will call them to pay out fee. If they can't pay the fee within one week, we will cancel the application.

If there is no respond after sending application form two days late, they can phone us.

For mail application, make sure that the cheque and application form are enclosing. If there is no respond after mailing letter three days late, they can phone us.

雖然明白，但也需要憑少許猜想，而且文法也需要一點修改

For customers（a few是沒有必要，因為多與少你都要serve他們）who live in distant area, communication via e-mail or mail will be more convenient to them so we accept their online applications and their applications through mail.（這裏應有多一句，因為沒有這一句，而進入下一句是怪怪的）

For online applications, after receiving their applications, we will request them to pay for the fee(or charge) . The application will be cancelled if payment cannot be made within one week. Customers can contact us by telephone in case they do not have our reply two days after their applications.

For applications through mail (cheque should be handed with application form), they can contact us by telephone in case they do not have our reply three days after their mailing.