Your crank arm is giving. If they refitted everything properly, then it could be that your crank arm is rounded off. Take it off and have a look at the taper. If it's not square, it won't sit properly on the BB and will only get worse.
@Radius started
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Your crank arm is giving. If they refitted everything properly, then it could be that your crank arm is rounded off. Take it off and have a look at the taper. If it's not square, it won't sit properly on the BB and will only get worse.