Acer India — Delivered wrong product and refuses to replacement or refund from Flipkart seller.

I ordered Acer gaming laptop on 25 November for studies ( price:49990 )rs
from Flipkart .But I received Acer one 14 (price :23000 )on 30 November .Now its been over 4 weeks and they didnt give me any resolution of this problem and also they refuses to replace the product . They are just giving me dates on dates, even workers of coustmer helpine are not answering me correctly .
When i talked to there seniors, they promised me to wait for 12 days(for there formalities)and insured that they refund my whole amount. But now its been more than three weeks and they didn't provide me any resolution.So, i request you to help me and solve my problem.