Try tightening this thumbscrew (marked with a red circle) directly below the eyepiece to increase the tension of the focusser so that it will hold heavy eyepieces. (Clockwise to tighten, anticlockwise to loosen)
Is the scope moving on its own due to its own weight or is it moving when you push it? The altitude tension knobs cannot ‘lock’ the telescope in one place (i.e.) the scope will still move if you move it. It is only intended to hold the telescope in the same place where you point it. The tension can be increased/decreased with respect to the weight of the eyepiece used. If the scope is moving by itself due to its own weight, check the number of the tube balancing system. It should be on zero by default (image attached). If not, you can loosen the two screws on the tension knobs with the provided allen key and slide the tension knobs to ‘0’. If the tension knobs are still not holding the telsecope, contact the dealer.
The tension knobs should be on ‘0’ by default.
The base’s tension knob cannot lock the base. Tightening it only increases the resistance with which the base moves. You can tighten it a bit to prevent the scope from moving due to wind. The base will move if you push it even with the knob fully tightened.
Hope this helps
Clear skies,
Lohitaksh