I have 2 heaters (baseboard type) in my basement. They seem to have a
mind of their own, and turn themselves on even when the switch (or
thermostat) is set to "off" or "zero".

I had a thermostat replaced by an electrician and he said the baseboard
heater was indeed working. Confused, it seemed to be ok for a while, but
then they magically turn themselves on and money is going out the window.

I removed a single 'breaker' from the breaker-panel that controls the
heaters in the basement. I dunno if this is safe thing to do, but it
turns off the baseboards and fixes the problem (temporarily).

What could be going on here?

Thanks in advance,
GKD