Is this a gas or electric?
Have you tried setting to 500?
you can't turn it up much higher than that, you need a new thermostat, your kinda stuck until the tech comes to install it
There isn't a work around unfortunately
Sorry, wish there was,
If it went to 700 you would be good, but it looks like the thermostat is off by 200 degrees roughly
Lemme know if you need anything else .... thank!