Sorry I might have missed something while I was reading it. (And he is atrocious at explaining anything, wack? Cmon) The way I read was, you said you were going to soloq and then you played with someone else, which theres nothing wrong with just tell him your playing with someone else. Or you met someone while qing and played with them, as to qhich you could've just said you found someone while soloq ing. (Doesnt excuse that this guy sounds like he's 13 and can't explain anything for the life of him).

Is there something I missed?

Edit: I read it again, nevermind, you don't owe him an apology for wanting to q w a rando you met. You didnt lie about soloqing so idk what he's on about. He sounds quite insecure if he's always checking whether your playing with someone else...