You need proof, go get a link showing your purchase, how much, and what the key price was for that day and calculate how many keys equivalent it sold for. You also need records of other past sales within the last 3 months.

https://mannco.store/item/440-starstorm-slumber-unusual-tough-stuff-muffs

One sold anyhow on November 7th for $183.12 and keys had an average price of $1.63 that day which I'll post a link for below. 183.12 / 1.63 = 112 keys

Key sales: https://mannco.store/item/440-mann-co-supply-crate-key

This one sold for basically buy orders, still a price of 247 keys may be questionable at best and there are other sales that happened that can be looked at too.