They were both out of the money so unless she had a bet on the other horse in the H2H market and deliberately rode to get beaten by Hatrick Boys (a la David Walker) then she has done nothing wrong. As far as I'm aware, jockeys have an obligation to ride their mounts out if they have a chance of finishing in the money, but no obligation to ride their horse out to win the H2H bets? Do they even know that they are in the H2H option?
That's the problem with H2H bets and the risk you take when you place a H2H bet.
I enjoy the odd H2H bet but there are certain jockeys I won't back in a H2H bet because I know if their mount has no chance of finishing in the money, they are more likely to ease them down than ride them out.
I suspect your email to the RIU will be in vain.