Opencart to amend the code of several modules

Acquired module affiliate program for opencart 2.
Module does not work correctly, does not charge a Commission to the ground.
-When ordering, you can specify a coupon code of a partner, it also is not charged a Commission.
-In the cart the correct discount calculation, weighing the item counts on 1piece and in fact 5, as a result, the discount amount is not correct
The author of the module not responding
-Upon check-in email to add account password
-In the shopping cart when you enter the comment to remove the reload basket
-In order history, amend the reference to text_pay on the button "proceed to payment"
-Add button "go to payment" in the email when changing order status.
-The catalog of products to remove the (0) in the category Novelties and Closeout