Downloading a plugin and upgrading

Hi, after much searching found the ideal plugin for me 'Subscribe by Email'. paid my money and began downloading as per the instructions. Installed the plugin to find I have a dasboard and nothing else, when I tried to download 'Subscribe by Email' I was invited to update my membership at extra cost before downloading the plugin.
Tried a few things, logging in again searched the help forum, tried the edit button next to the API key but still can't download without upgrading.
I would appreciate your help with this problem.
Regards
David.