Touch screen both erratic and unresponsive

Here's what's going on.

My Ipod nano gen 7, I have had it for almost two years now, and it is just a glitchy mess.

What happens is that the touch screen has this very erratic behaviour: tapping and swiping without me touching it.

On top of that, certain areas of the touch screen are completely unresponsive.

I am fighting a war with my ipod every time I want to select a song or change the volume (the volume button on the side has lived its life and the on-screen volume bar is part of the unresponsive club).

There is no water damage. The touch screen has a single crack, been there for months, erratic behaviour started before this. Online posts say that a possible cause is the large amount of memory I could be using, well, out of the 16Gb on my ipod, I am using 7. Resetting the settings does nothing.

Does anyone have any advice for me? I don't have enough money to buy a new Ipod.