I could not understand his answer, when I asked what company he was from.  He had a very heavy accent, maybe from India.

Likely a character looking to steal from you. Random calls from foreigners rarely supply anything good so it's not a bad move hanging up on them as soon as you notice an accent.

Rang once. I don't answer unknown numbers. No vm left. Blocked!!

Green energy committee. I've asked 6 times to stop calling. Solar panel sales.