The OP does not clearly establish that the offending pax was bumped up to biz. For all we know, the lady and kid could have paid more than the OP for a biz-class ticket.

I like the FA's quip, when OP pointed out two coach seats: maybe -you- should take those seats. Again, from reading the OP we do not -know- how the woman got into biz-class. She could have been op-upped, but she could have also paid full fare. She might have been non-rev. You can't judge a book by its cover.

A complaint of this nature probably deserves to be addressed by snail-mail instead of e-mail. Anyone can say anything they choose via e-mail. There's no way to prove a claim. OTOH, a snail mail containing photos of the damaged computer, a receipt for the new computer and new software, etc. would go a long way towards eliciting a satisfactory response from AA.