WIX API for paid membership

Hello,

I am working on a community club membership website in which we are planning on allowing member to pay an annual fee for club membership. This allows them to access certain areas of the websites (similar to Wix paid membership plans).
Our plan would start May 1st 2019 and end May 1st 2020 irrespective of when the member sign’s up. For example, if the member pays in Sep 2019, the membership should still end on May 1st 2020. Currently paid membership plans by Wix does not support this.

So far I was able to figure out how to use API to accept payments.
But was not able to figure out how to allow member access if a member logs in or how end a member access after certain date.

How can I achieve this by using Wix API?

I am new to Wix and webdesign. Therefore any help is really appreciated.