Technical issues (GM 24-70 2.8)

Hey everyone, I’m having an issue with my Sony 24-70mm f/2.8 GM (Gen 1). The electronic contacts on the lens mount have developed deep grooves from wear, and I’m pretty sure that’s causing communication problems. The lens sometimes darkens while zooming, which makes me suspect intermittent contact with the aperture control. I’ve tested it on two different camera bodies and the issue persists, so it’s definitely the lens. Has anyone here had the contact board or mount contacts replaced on this lens? If so: What did it cost you? Did Sony replace just the contact unit, or were additional parts involved (flex cable, aperture module, etc.)? Was it worth repairing compared to selling it and upgrading?