I can see both sides
It was a little rude for the seller just to sell to someone else and not inform you straight away.
However, if he DID contact you and say, sorry but someone has offered me cash on the spot, and i need the cash asap, so i sold it. Sorry to stuff you around . . . would that be ok with you ? I would be annoyed, but, accept it because i can appreciate the situation he was in.

On a further note. Did you ever accually CALL him, opposed to texting ?
Texting is a weak way to communicate, especially when buying.

In the end, i think the seller was slack not to contact you straight away, but, life goes on.
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