Being in Canada attempting repairs myself prior to contacting the manufacturer or returning the item is always first choice.
I did spend several hours dismantling, examining, poking and attempting to re-assemble my defective units. I could find nothing in them that looked like it had failed and was not sure I had got them back together properly. The requirement to be "very dexterous" seems to be an understatement!
This is not a well thought out system and I am surprised they were released at all unless prototypes were never tested.
Steve