Apollo Pharmacy — Apollo BP machine not working which is with 1 year warranty

Purchased Apollo BP machine in Hyderabad, Kukatpally jayanagar branch with1 year warranty complained several times but staff is not responding, every time asking me to come later. Now they are tellin g that I have not purchased from them like that, I have online proof that I bought from them, even they also confirmed few days back, what to do now?