Are you referring to a tone generator? If so then you should only need the one. My bloke has tinnitus in both ears equally and needs just one generator, which he began by wearing several hours a day but now (less than two years later) hardly needs, so effective was it.
The tone generator, sqad, is a small device that emits something similar to white noise but at a different frequency. The idea is that it trains your brain to tune out the frequencies highlighted in tinnitus, which are normal frequencies for most of us but which those with tinnitus have become super-sensitive to. That's because tinnitus is also a brain thing rather than a purely physical ear thing - hence why my bloke only needs the one generator.
Msemma, if wearing your original tone generator isn't having any effect any more, then I suggest you go back to your GP and get yourself re-referred to your specialist (unless you can go straight to the specialist). Could be you just need some sort of upgrade.