If the OEM wont cooperate, its incredibly difficult to find exact replacement battery contacts unless you happen to live somewhere like Shenzhen. Anyone with a stamping press can make them and the setup cost for custom ones is fairly low, so the main hurdle is simply identifying who's making a compatible one
If a battery contact hasn't corroded away too much, its usually possible to restore satisfactory operation and reliability by cleaning off all the corrosion with a fibreglass pencil brush or fine grit wet&dry paper, then tinning the contact with solder and brushing off as much as possible to leave a thin tinned surface to resist any future corrosion. N.B. some disassembly is likely to be required to aid removing the corrosion and avoid heat damage to plastic parts.
Otherwise, you can probably make a replacement tab from phosphor bronze shim stock. Unlike ordinary brass, phosphor bronze is resilient enough to be used for springs. Tin the contact faces and tail to be soldered to the PCB before fitting.