Dindsy
You need to remove the eyepiece or put the lens back on the camera. The light rays coming out of the eyepiece are parrallel. The camera needs diverging light rays (usually the job of the lens which converges the rays which eventually become diverging) and through focusing you align the sensor to the corresponding focal plane of your subject. Having the eyepiece in the optical train will mean it will be impossible to focus the image in the camera.
This may not completely fix your focusing problem and you may still require an extension tube, but at least you will see some change in the image when turning the focus knob.
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