It may be possible to bypass or mechanically hold the battery-door microswitch in the closed position, but the safest recommendation is to take the camera to an independent camera repair shop.

Based on the community answer, an independent shop may be willing to disable or secure the switch so the camera sees the battery door as closed. Canon service would be unlikely to perform that kind of workaround, but for a repair technician it could be a simple fix depending on the damage.

Because this switch is part of the camera’s power/battery-door safety system, a DIY override could cause unreliable operation or further damage if done poorly. A technician can inspect whether only the plastic actuator broke or whether the microswitch itself also needs repair.