Top Dawg 720p DVR Dash Cam w/ 8GB SD

I bought one of these in March, and discovered it had an unpublished ability. It is an effective GPS jammer, preventing my TomTom unit from getting a signal. I guess the TopDawg unit is poorly shielded and designed/constructed, but in any case I can’t use the dashcam and GPS unit at the same time.

Not sure if have a detail manual or a customer service line. Afraid bad after-sale service.