Nah, they (sensorless) aren't that bad.
According to my 2 second Google search, it's sensored anyway. Make sure the sensor leads are fully in, and that you haven't plugged them in the wrong way round (they are polarity protected, but it seems easy to still plug them in the wrong way round). If you've got another sensor lead, try that.
Also, put the ESC on sensorless mode (if you can), and unplug the sensor lead. If the car will move ok (it might cog a bit, but it will still move), then you can narrow it down to sensors - they are often the first things to go in general.
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