I had a damaged wheel on my luggage during a trip to Thailand and tried several local places that advertised "Bag Repair", but they were unable to repair damaged wheels on Luggage. I think they are more handbag repair places, rather than full sized luggage.
In the end I went into Mr DIY and bought some wheels in there that I do not believe were made for luggage, but fortunately matched exactly with the holes on my luggage, along with some screws and bolts, a small screwdriver and pair of pliers and repaired them myself. After another trip to Thailand since then the wheels are still good and holding, and much cheaper than buying new luggage.
They seemed to have a whole section of loose swivel wheels on metal bases of different sizes, along with some pre-packaged sets, so perhaps worth checking if the existing wheels can easily be removed from inside and then a trip to Mr DIY (Stores all over Bangkok can be found on Google Maps) and then making some new holes in your existing case to make the new ones fit, if they need four holes like the ones I got.