Question Wireless headphones hissing

[BenX41]

Had to replace my Acrtis pro wireless headset after the batteries had broken and the left side cracked, however the replacement pair I got hisses constantly after being turned on.
I've no clue why it does this, I've tried suggested fixes like turning the sidetone off and turning on the volume limiter, but its still there and headache inducing.

I'm no audio expert by far, so I'm not sure if there is a workaround for this using a cable/adapter of some kind?
Clutching at straws here as I've no clue what to do about getting a replacement refunded.

 

[hang-the-9]

Test it with a few sources. If it does it on all of them, return them for another set. About how, the place you bought them from is a good start or contact the vendor support.