With NAC, I ended second place with equal points as number one Heracles. But I got 6 training camps against me, while Heracles received 0. I would easily become the champion if I haven't received so many training camps. Quite unfair I guess?
Max of training camp
Sorry to hear you lost on goal difference, better luck next time.
First, know that training camps are part of the game and everyone has equal number of them and can use it how they please, so it's never unfair when other managers use theirs against you plus if you don't like the training camp option you can always create your own league and disable them.
Secondly, while you can see the number of camps used against you and which teams used them, it's impossible for you to know which teams used training camps against each other and how many camps each team used and take against them. So you can't know for sure if he was camped or not, maybe he even got more camps than you.