Offline Installation - Enrolments


I have successfully setup an offline installation on a Windows machine with NodeJS and MongoDB in my school for 115 students. We are a school in a rural area and our bandwidth is severely limited by our location (we have 15mbps for 550 learners and 100 staff). I have tried getting a class of 24 to use online but our bandwidth is woefully inadequate.

The offline installation works perfectly expect when purchasing enrolments. It gives me a price of $1 per enrolment but when I enter card details it generates the following error:

2016-01-25T09:03:32.235Z - debug: 500: Database error, Error: No such token: tok
_17X6FfKaReE7xLUdO5pMJLoX; a similar object exists in live mode, but a test mode
key was used to make this request.
POST /db/prepaid/-/purchase 500 3358ms

Are offline installations still pay-only for enrolments? If I am using an offline installation is it possible (and allowed) to manually add a payment entry into the MongoDB table?