unreliable

My Salus rt500rf programable thermostat is acting bonkers. Had it working fine for 6 months, now its going crazy. It has been used on its factory settings, 22 degrees, manual and no programed on/off times. In the early hours of the morning, around 3am/4am it ignores the set temp on the unit and...

So I have 5 of These (LT FRD12DL) in my bathroom as one may know, and was just wondering how many others on here have had issues with ones purchased in 2012/2013 failing after two or three years? Mine were purchased and installed in 2013, and I have had to replace 3 different ones out of the 5...