Yorkiegirl, I'm not a scientist, but I can't see how a faulty microwave could heat the bowl but not the food.
Have you tried your bowls in Helsi's microwave, for instance?
Could you do some trials with a cup full of water and 1 minute HIGH with various different bowls.
(If m/w is working OK and bowls are really m/w safe the water should be almost boiling, but the bowl cold.)