Airtel — prepaid sim issuance

I am currently using an airtel postpaid connection. But i find it slightly expensive and hence wanted to shift to airtel prepaid. So i went to airtel office in electronic city, bengaluru. So the first time, the staff sends me away saying that we are out of sim cards... Outage of daily cap has happened. Now i don't know how far true that was.
Anyway, so i went there again and they say"you should come before 6pm... Can't help you now." what sort of a behavior is this? Will somebody tell me a more convenient way to shift to prepaid??

Ps : the exact address of that office:
16, neeladri rd, karuna nagar, electronics city phase 1, electronic city, bengaluru, karnataka 560100.

Please take some action against them. This is not the way to trear your customers. I won't think twice before shifting to vodafone if they give me better service