Frameboxx Institute — in regards of my certificate

The branch in delhi south ex of frameboxx is not giving me my certificate even i have submitted my full fees. And the authority (Mr. Mayank karnwal) is continuosly avoiding my phone calls.
They dont even provide me my invoice no. And now not responding me in any or the other way.
I am not able to go there and they are not tready to pick up my phone, what should i do?