SBC Global DSL Problems w/ OS 10 Help !

I have an SBC Global DSL network in my home and need to get my old G4 i-Mac working on a 2 wire hookup but it keeps kicking out and Tech support is of no help. I need to get the drivers for later versions of system 10 but are hearing rumors that OS 10.10 or 11 are possibly part of the problem. Can you help me download the DSL drivers i need or give me some good advice where to look for help.

Thanks Italian Truth