Hi, please go here

https://my.wealthyaffiliate.com/account/subscription

And cancel billing.

You need to cancel the membership yourself and before your renewal is due otherwise you will be automatically charged as per the T&C

Also if you own your own domain and have it hosted here it has to be moved to another hosting before you cancel.

Here is a link what will shown you how to cancel Cancel Wealthy Affiliate Membership and Stop Billing