Hi my electric hand brake won't work i have changed the calipers and it still won't work it's a audi a6 c6 2007 anybody help please

The electric handbrake (electro-mechanical handbrake or EPB) to give it it's correct name is usually pretty robust. You'll probably need to scan the car to see what error logs are there. My wife has a BMW i3 and she had similar issue, however I traced that to the physical switch.

Does the handbrake button illuminate, but no handbrake? Usually you need VCDS if you're swapping rear pads for example, to place in the service position. There are some YouTube hacks including 12v power-supply, but I would avoid unless you want further issues. Speaking of batteries, you can get issues with a failing battery too. If it's old - then consider swapping it out. A new one needs coded to the car. Check the fuse too.

You can get VCDS from Gendan for around £200 and find an old laptop to run it on. Best money you'll every spend.

Tried all of the above still no joy thinking wire problem