Yes I stay in Mumbai too and I've known some institutes for sure which are pretty famous for the Mht Cet law 3 years course entrance exam. I'll enlist down some famous classes that I know..

1. IMS GHATKOPAR
2. PRAYAS ACADEMY
3. STUDY CAMPUS, ANDHERI
4. IMS CHURCHGATE
5. IMS POWAI
6. TARA INSTITUTE

You can search about this institutes, their contact numbers, location, etc on google and contact them.

Thank you.