Holy misinformation batman.
When a pedal calls for say, 300mA, that is the MINIMUM the power supply should be. You could run a 300mA pedal off of a 100gazillionA power supply, and as long as the voltage is correct, you are fine. It would just be a waste of a huge power supply that can handle a lot more loads on it. If you are running two 300mA pedals, then you would need a power supply rated at a MINIMUM of 600mA.... Usually it's best to go higher.....
In your case, something else was fucked up......