Credit subscription dont works

Hello, ive a problema with ur plugins. Actually im using yith woocommerce membership and yith woocommerce subscription to make a plan by credits for customers downloading product.

The problem its when a customers buy a plan (with 10 credits) and dont works when make a download product. The credits dont low when make the download ??

Some tutorial to use good membership and subscription plugin and sync the product to the plan for low credits?

Thank you.