MailMunch removing subscribers

I recently used Mailmunch to subscribe people to one of my on-line class lists at Constant Contact. A few days after implementing Mailmunch, my other Constant Contact lists were losing subscribers. That is, it appears that Mailmunch took people off my other lists if they subscribed to my new on line class.

I am furious – hundreds of subscriber names are now gone! I contacted Constant Contact support and here is what they wrote to me:

The API integration called MailMunch that is connected to your account was updating contacts and removing them from the existing lists they were on.If you have any further questions as to why this integration was updating your contact’s list memberships, I would recommend reaching out to the creator of that API.

Mailmunch was supposed to add names – not delete them!!! I am outraged that this app would REMOVE names from other lists in my account.