Need a professional plumber!!

Hi all,

I've got a bathroom sink which is not draining properly. After working on it for a while I realized, it's connected to a double kitchen sink on the other side of the wall. I've to suck them both with the wet and dry vacuum, also I've plunged until my face has become blue. After trying all these still, the problem persists. What should I do now?

Should I contact a professional plumber or are there any chances that I can fix this. One of my friends had given me the number of a plumbing service in Toronto. But I haven't heard about them much. If someone over here knows anything about this service provider feel free to share your suggestions and experiences about them.