We have purchase a R.O. from Aqua guard through Service Engineer (Mr.Vikash Gautam Mo. No. 09837049790) from Meerut on dated 25/04/10.He is saying to after installation, we are not responsale for any query.he confirms us that he would sent the orignal invoice in 2-3 days.but he has not send any invoice.we have called him many times, but he is not given any responce for it.