Croma — AC installation charges

TC[protected] AC installation charges.
AC installation was done 4 days after the request was raised. I had to call them to follow up on the status everyday. During this calls, I asked about installation cost. Customer service rep said it was free for standard installation. Not once, I got confirmation from them twice. Ac installation is done today. Service rep asked for 999+ tax for standard installation along with other extra charges. I argued it was free as informed by Croma customer service. We went into quarrel because of that. And today one hour back when I called customer service in a conference call, customer service rep said it is not free. It is chargeable. I finally had to pay him. Multiple mis information provide by the reps. I was embarrassed in front of repair persons. Need revisit this and give me proper solution.