battery acid damaged batt-compartment - how to restore?

Hi together,

I own a Apple Magic Trackpad, where the batteries ran out and damaged the battery compartment.

I removed the batteries and cleaned the battery compartment. Now, the batteries have a little bit axial play (2mm?), so I have to put some metal spacer in between. And the Trackpad is only working sporadically, I suggest a bad contact problem.

When I look into the battery compartment, I only see a elastic radial spacer and a (always corroding) center contact.

Does someone has any suggestion, how to resurrect the trackpad? Is there any part missing in the battery compartment? A spring maybe?

Pic of contact