How to sell to every email subscriber even they are moving chaotic in my email automation

Hey,

I m having this problem for years.

This is how the things are:

- I have 10 digital products (ebooks) to sell on my website
- I have an a good responsive email list and I m selling those products to that list
- I have email sequences with approx 20 - 25 emails each to sell every ebook to the list - something like Sequence 1 is selling Ebook 1, Sequence 2 is selling Ebook 2 etc.
- I have an automation system so when someone is subscribing, he will theoretically go to each email sequence
- If the subscriber is buying Ebook 1, he will pe put in the Sequence 2 for Ebook 2
- If he isn t buying, he will be put in the next Sequence 2 after the last email from Sequence 1

My problems are when:

- website visitors buying Ebook 5. My system it will put this client in Sequence 6. So that client will not be in touch with the marketing from Sequence 1 to 4.
- subscriber in Sequence 1 is not buying Ebook 1 but is buying Ebook 7. So he will pe put in Sequence 8, without being in touch with Sequence 2 to 6


There is any course / book / seminar etc. that will teach how to make a good strategy for this kind of situation?

There is any Email Marketing platform that can perform some automation so I can put those visitors / subscribers back in the right sequence?