Peugeot 307 headlight not working

Whenever I start my car after parking for long time (during the night or after work), the left side headlight (low beam) is not turning on. Only the right side headlight is turning on. I need to open the bonnet, open the circle cover at the back of the headlight and wiggle the lamp to turn it on

There was moisture forming inside headlight cover 3 weeks back. A mechanic opened the headlight cover to remove moisture. He kept a polythene sheet below the headlight cover to prevent moisture forming again.

He also replaced the lamp (low beam) inside the headlight.

Any help please? I don't want to consult that mechanic again as he is using all unprofessional techniques like inserting a polythene sheet and everytime wiggling the lamp wires. Wiggling has damaged the lamp wires also once and made it loose connection. Now, another mechanic corrected the loose connection but the problem of not turning on remains still.

Thanks a lot in advance please.