I asked for a refund to Apple and received just a part of it

It looks like you got 3 refunds for something that you purchased over and over. As all purchases are final, Apple gave you 3 refunds out of the goodness of their hearts, they didn’t HAVE to refund anything, but you continued to repeat the purchases. That sounds fair to me; if you don’t want repeated charges don’t make repeated purchases. They were very generous to refund anything.

Then you will have to take it up with the seller. No one in this user-to-user forum can help you.

That’s sad.

what do you think your fellow users can do about it?

This is a user to user support forum.

Apple or whoever you want a refund from is not here.

You made those purchases. Apple will never charge your for something you didn’t authorize. If the vendor didn’t deliver your dispute is with the app vendor, not Apple.