WP Membership Bug

We bought some time ago a plugin for wordpress called WP-Membership, we are suffering various problems with it but the worse one is ocurring in a client website. The plugin connects to a server where it retrieves a security key to work, we dont know why but it looses the security key so the plugin gets deactivated till you reconnect it again. We have tried all ways to contact the support staff till last August and we dont have any answer so our last option is to find someone able to fix this problem. Please find attached a copy of the version that we are using.