I would think that you would either need to bring it back to whom ever did it for you, since they obviously failed to do the work to your satisfaction, or YOU are going to have to do the work that they did, basically all over again. If it were just a language issue, I think that could be easily resolved, but they have all the apps and the OS incorrect, so more needs to be done. So, if you do not want to have them fix it, I think you are looking at reflashing your phone. I just went through all of that and it is difficult to wrap your head around the concept if you have never dealt with it, but once you see how it works, it becomes much easier.
I'm sure someone with more experience in this area may have another suggestion, but the above represents my 2 cents.. Can you just bring it back and have them correct their mistake????