45 days? Lol I spent 10k under 10 days, just paid electricity bills and bought some gifts card on Amazon (it was giving 100 cashback etc. + card's usual 2% cashback), some offline shopping and voilla, fees was reversed, I had loaded the card with some money though so the overall I wouldn't end up spending 100% of the credit limit.
I had received my card on November 4, and joining fees was reversed on 15 November