Hey bob01dog,
I assume you have no experience with disassembling stepper motors? If you have, that would be the most correct way to replace the wires and maybe additionally to put a strain relief on the cable to prevent happening this again. I would also see the possibility to simply cut the wires where the breaks are and resolder, but you have to be a master in soldering with that short ends. Another possibility is to cut at the cable breaks and crimp wire ferrules to the wire ends, which then can be put into screw terminals or screwless terminals, e.g. into a WAGO through connector. Wire ferrules would have to have the size matching the wire gauge exactly. The color code for wire ferrules is here.
There are also butt connectors like this insulated for 0.5 – 1.0 mm² or for 1,5 – 2,5 mm² or this non-insulated for 0.5 – 1.0 mm² or this for 1.5 – 2.5 mm² (needed dies: 974910 or 974930 for non-insulated or 974906 for insulated connectors) that can be directly crimped on the wire ends. See here for details on tools needed. Here the same applies as said above: Crimp tool and crimp connector is required to match wire gauge!