Left side of JBL Headphones doesnt work/works again

Hi everyone, my JBL Bluetooth headphones' left side stopped working suddenly. I purchased these 3 months back. Havent dropped them, bent them, etc.

The left side stopped working but then started working again if I gave the headphones a slight tap on the left side of the bridge/ear cup. However, since a few days this solution stopped working too. The other day I was looking for solutions on the internet and a YouTube video had like real bad audio so I had to turn the volume all the way up and VOILA! The left side works again. Now this is happening everytime. The problem exists in both wired/wireless(Bluetooth) modes.

1. The left side doesn't work initially
2. I maximize the volume on any loud song.
3. Left side starts working again albeit a bit slower than the right one.
4. Repeat 1-2-3
5. Can anyone tell me what the problem might be and how can it be fixed? Can I do it on my own? I can't really afford to buy new ones so will have to do away with trying to fix these ones. Any help would be highly appreciated. Thanks in advance.