I was hired as a developer in a Team-A. I needed inputs from another team so I didn't have much work to do for long time. But during this time I voluntarily started contributing in another Team-B. Eventually over a period of a time, I was the one who developed almost all parts of the solutions. But this Team-B hired a new employee and made him owner of the solution I developed.
I was disappointed but I stopped working for them at all. They tried to pull me many times but I refused it directly. Also my manager at that time was not supportive.
Meanwhile my manger also changed. I got the job in another company but the new manager asked me to stay and gave me good topic to work. We also had an verbal agreement that I will not work for Team-B at all. Everything become good but after a while, my new manager started pushing me to work for the Team-B again. I don't want to work for them as they never appreciated for my contributions. What should I do now. Thanks