Thermostat Concern......

I purchased the BAH 1000 from Big Apple. It finally got plugged in today. I set it for 83 degrees. The light came on. I went back in a half hour and the light was off. The temps stayed at 70 degrees on the outside of the hide on the warm side as well as on the inside of the hide on the warm side. I bumped the temps up to around 85 degrees on the thermostat and the temps did not change. I went under the substrate to feel the uth mats and they were both COLD......what the heck?
I just went back down there and bumped it up to 90. The light came on....so I'll check back in another half hour.
Has anyone else had issues with this thermostat?
I'm quite annoyed as I have never had issues with the heat mats and I have NEVER used a thermostat. I was told I have been lucky so I went online and ordered a good thermostat. Now my temps are wayyyyyy too cold.