I'm sorry to hear about your difficulties with the Kazam 540 Trooper. As a first step I'd recommend rebooting the handset completely to see if it comes back.
If not a full factory reset of the handset may be required. This will wipe everything from the handset itself including photos and contacts so you may wish to back these up first.
Once you're ready you can do a factory reset by following these steps:
This should get you your keyboard back but any questions, let me know.
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