flx 4 jack problem

hello,

everything was fine for months and now when I plug in headphones, earphones or anything else it only gives me sound on the left earphone. 

I'd like to point out that I've tested on my phone none of my sound devices are faulty, the problem comes from the flx 4. 

can someone help me on what to do to repaire my flx 4 please ? 

sincerely