Royal Enfield — no proper response from dealer

I have booked a stealth black 500 cc on march 15th, after series of calls they told me the bike can be collected on 12 the of april once i reached showroom the bike was faulty, they promised an exchange in 2 business working days. But i neither received a call or message after 2 working days i have been calling them from past 2 weeks yet i didn't get a proper response about my bike. They promise a call back and never respond back and half if the time they never pick up calls