How to get residence proof for FRRO registration? (Chennai)

Dear all,
as I am staying more than 6 month I need to register with FRRO and it already gives me a headache. So finally I got most of my documents together, but only my residence proof (Form C) is a problem and thats why I would like to know, how you guys did it. (see: Protected content
a) I am currently only living in a temporary place and dont know my landlord who could potentially fill out this Form C for residence proof, plus my roommate wasnt sure about it. Did anyone of you just went there with copy of elictricity bill and that was enough? Which documents were accepted?
b) I tried to fill out this Form C for my company adress myself, but that was also not working, because you seem to have to be registered only to get the form itsself. I would rather like to register with the company adress, but I am also not sure how to do that if I dont get the official Form C. Could I just go there with a letter from my company?
Would be glad to hear how you managed the registration thing!
Thanks, Anna