How to screw up the acceptance of payments (PayPal) in an online store in such a way that the client would ascribe something else in one form before paying?

Question

Programming

There is a landing (online store). it is necessary to attach a form of payment so that the client suffers at least
9 pcs of products, with different prices, and when ordering each, the client must be able to enter specific desires.
clicking on each product, the client should see a form where he will enter his mail, his text, special requirements if available, after that he clicks on the Buy now button. That is, each product has its own form, where in the title is the name of the product with its price and fillable fields and the Paypel payment button. After that, a letter is automatically sent to the client’s mail saying thank you, you have ordered such and such a product, after receiving payment, you will receive it within 24 hours. That is, I chose a product, filled in 2-3 fields and paid. All! and so on for each product. but it is necessary that all this is not blocked by Paypel later. How to do all this and who to contact? Thank you for the detailed answers in human language, since I am zero in programming