My Duraflame DFS-550-0 electric fireplace stopped heating

'm sorry, I couldn't find a parts diagram specifically for the Wonderfire 2570 direct vent free standing fireplace. However, safety switches in fireplaces are typically located in the control compartment. The safety switch may be a thermal switch or a microswitch, and its purpose is to shut off the gas valve or blower motor in the event of an overheat condition or other safety issue.
If you suspect that the safety switch needs to be reset, you may want to consult the owner's manual for your fireplace, as it may contain instructions on how to reset the safety switch.

Battery in the control perhaps ..........................

google a manual to find its fuse

http://www.electricfireplacesdirect.com/pdfs/duraflame/DFI-550-36-37-38-39-40-QVC.pdf

https://www.meijer.com/assets/product_files/pdf/duraflame_large_electric_stove_red_owners_manual.pdf

The thermostat at my husband's business didn't work last winter and neither did a lot of the electrical outlets. We called in an industrial electrician. Perhaps you can find an electrician online who you could call to help you? I think that would be best. They would do the job for you and you wouldn't have to go anywhere. Industrial Electricians and More in Lethbridge Coaldale

There are little light bulbs (like large Christmas lights) that have probably burned out.
remember to replace with only the same wattage and type.

a popped breaker is a short in circuit, first check cord for damage, second it could be heater shorted to block. best checked with multymeter on ohms scale, circuit through block heater is usually 25 to 45 ohms.

Two items, check the thermostat is not set too low.
If it is not, then check the fuses.

sounds like the heating element is going bad..its probably intermittant..