sethi Telecom — Internet connection not working

Respected sir/madam myself Deepak Sonker and i have taken an internet Connection from Sethi Telecom,whose address and phone number is as follows: Sethi Telecom ,Auth. Buisness partner: sify Broadband, B-11/7,sector-18,rohini,delhi-110085, mobile number: [protected].
sir the matter is that i have taken an internet connection from this sethi telecom 2 months back, sir internet connection breaks down and they promised me that u will get 512kbps speed of downloading, and they are not providing me the speed they promised and connection breaks regularly interval of time , when i complaint throgh phone they told me that they are going to send the boy with in few minutes but the boy didn't came and i got disappointment, sir i m totally fed up from this sethi telecom, kindly take necessary action against this company as soon as possible, i will be very greatful to you,
thanks
my contact address is :
Deepak Sonker
Flat no 12,pocket 24,sector24,rohini,delhi-110085
ph: [protected]