Protected Content using wrong Instant Payment Notifications URL

I have noticed a lot of members are being "deactivated" which I was told in your live support was a result of an admin manually deactivating their account. A few days later (yesterday) I receive this notification from paypal:

Please check your server that handles PayPal Instant Payment Notifications (IPN). IPNs sent to the following URL(s) are failing:

mydomain.com/ms-payment-return/paypal_standard

If you do not recognize this URL, you may be using a service provider that is using IPN on your behalf. Please contact your service provider with the above information. If this problem continues, IPNs may be disabled for your account.

Thank you for your prompt attention to this issue.

So now I realize the plugin is not using the proper URL which is automatically deactivating all my user accounts! Need this fixed ASAP!

-NOTE: support access granted already.