You need proof of what keys were selling at at the time of the marketplace sale. For example, keys were selling at $1.9 on July 1st, so that sale would be 42 keys, not 44 keys and you would need a screenshot of the marketplace sales graph showing the price of keys on July 1st.

You're also missing several in date sales off of marketplace. for example, there's this sale for 42 keys

https://backpack.tf/profiles/76561199059160806#!/compare/1631750400/1631836800

https://backpack.tf/profiles/76561198120175506#!/compare/1631836800/1632182400

Looks like there are at least 5 other sales off marketplace that you need to track down