Amazon company - They aren t providing the resolution which they promised about

I ordered a Samsung galaxy a** *g smartphone on **th October and called again on **st October and complained about the heating, battery drain and performance lag issue so a executive named Miran told me that since you have called under the expiry date of replacement so, we will be with you till your issue isn't solved and told me to call again after *-* and tell your problem again and till date when you call your replacement period will be expired so, we won't provide replacement, we will provide you refund......and when i called them today they are talking very rudely and first time ended the call after holding for ** minutes and second time they said we can't do anything and third time they said "we can't comment anything about what our executive promised to you"
That's the issue!