I have not used OverPlay personally, but the homepage does suggest that it supports OpenVPN protocol. If yes, you should be able to use it from command line. Here's a short guide I wrote
https://www.linuxquestions.org/quest...os-4175632515/
It's for CentOS/OpenSUSE, but I strongly believe that it'd work on Mint too, since the commands are pretty generic.
You may have to contact OverPlay support to get the configuration files, certificates, keys etc though.