InmateAid is not a replacement for GTL or a portal into their system. What it provides is a local phone number matched to the same rate center as the jail, which triggers GTL's lower local calling rate rather than the more expensive long-distance rate applied to numbers outside the area.
To activate the savings, you need to add the InmateAid local number to your GTL account rather than keeping your original number as the contact number. You can do this by calling GTL directly and placing the local InmateAid number on your AdvancePay account, or by logging into your GTL account online and swapping the numbers there. GTL does not charge a fee for that change.
Once the InmateAid local number is in your GTL account, your inmate calls that number, and GTL charges the local rate, which is several dollars cheaper per call than calling a long-distance number. On four or five calls a month, that difference adds up to more than the cost of the InmateAid service.
On the refund question: InmateAid does not offer refunds once a line has been issued. Phone numbers cannot be immediately reused under federal regulations, which creates a real cost on their end when a line is activated, regardless of whether it is used. The service works as designed for GTL facilities; it just requires the extra step of updating the number in your GTL account.