Intermittent Power?

The electricity cuts on and off when the flex is moved up and down near the unit end of the cable. I am therefore sure it is simply a loose connection. I just need to get access to where the flex enters the unit, near the on off switch. HOWEVER this seems to be sealed unit and without levering the plastic parts and probably damaging the unit, I cannot gain access to rewire the problem.....Help...how do I get IN ?