I know how you feel, this seems to be a consent problem with the Streetka. I recently had my passenger door handle replaced and bought the part off ebay myself then got a local garage to replace it for me which cost £40.00. I wouldn't advise doing it yourself as it's a really fiddly job you have to drill out and and replace revits on the side of the door. To prevent this happening I spray all my handles (inside and out) with WD40 every couple of weeks or so as they tend to get quite stiff which then causes them to brake. Hope this helps. :)
The problem isn't with the handle itself but where the cable goes inside the door behind a box to the door release. Because the handle is weak it breaks when the cable has too much resistance.
I figured this out when ours became very stiff so I took the door card off the when I pulled the handle I noticed the plastic box move so clearly it's not big enough to house the cable as it pulls and turns and this puts back pressure on the plastic handle.
So I cured it by pulling the plastic box away from the door-it's sealed on - to give the cable more room to move. And then spraying loads of 3-1 oil (NOT WD40) inside the plastic box and all along where cable release travels helps it move without rubbing.
I can confirm that since doing this on both doors 2 years ago both handles still work normally without any stiffness. Simply replacing the handles does nothing and they will soon break again.