Hello,
we ordered a Carbo x in november and received it 3 months later by the end of february and have a similar problem.The bike worked just fine and after a short period it just won't power up. That is to say, only the "walking-mode" (which allows a user to walk next to the bike and the motor will go up to 6km/hour) works. So I wonder how your problem was resolved in the end and how long it took?
At this point we lost all trust in Carbo since we made a support-ticket weeks ago and kept returning with very slow answers and demanding tests, video's,pictures and detailed description of the problem.
Finally after a few weeks they came up with the solution of sending out a controller and a torque (which we should replace ourselves) and after a week of silence, not knowing if the parts were send out, which we kept asking about,
to come up with a new idea : We want you to run an extra test to be sure we got the problem right and will let you know later. So, not only they did n't send out the parts but they let us wait (after allready waiting for a solution for more than 3 weeks) to let us know which new extra test they want us to perform...
grz