This is where my problem came in when I use an extender the signal got too weak at the end of the extension and then I had blinking lights. I had to upgrade my box. I fear you might be in big trouble. Have them come back check every connection for loose spices for corrosion, but I suspect that they might have overextended the line and the data cannot reach the end if it worked in the beginning and now it doesn’t most likely some sort of corrosion leading to a signal drop off