Hello,
I'm sorry to hear that you're having issues!
If the devices are new, out of the box, then they should have one month of RMS for free. If bought used, most likely someone has already used this free month.
However, if it is new, then adding it should be as simple as entering the LAN MAC address and Serial number into RMS. What error message is it showing?
If more credits are needed, they can be purchased by contacting your sales manager or via our trusted partners.
Best regards,
DaumantasG