Wordpress and wookommerce

There is an online store. 2 problem.

1. We want to introduce electronic gift certificates there.
Conditional, at 2000 p, 3000 r, 4000r, 5000 p.

When you buy a certain certificate, the buyer receives a letter with the code.
Next, he can choose any item using this code (there is a "coupon code" in the basket at checkout)

Further: if the amount of the goods is more than the amount of the certificate (for example, the certificate is 3000, and the goods are 3200 rubles), the buyer should get out the field where he must pay extra.
If the amount is less, the balance burns.

If this is real, it is important to understand whether we can form the codes ourselves, they have recommendations for compilation (small letters, large and small letters, through the dash, etc.)


2. When buying the buyer comes to the post office check without the name that he bought (price only)
ATOL (the company that forms the checks) said that the problem here is that it is necessary to set up a connection between the online store and the bank, so that as part of the basket the bank was transferred the full name of the subject of calculation.