Contact them.
If all your earnings were removed then it sounds more like it was a breach of contract.
Several ways this can happen.
Main one is artificially generating traffic for the domain, by buying traffic / offering incentives to anyone that clicks a link / forwarding other domains to the parked one.
Other ways are using software to artificially create click throughs or just clicks.
Or if you or someone else clicks on the same links too many times it is counted as trying to cheat the system.
In any case contact them as soon as possible to resolve it, if you leave it too long they might take it as an indication that you are guilty of one of the above ... or one of many other ways.
Let us know how it turns out.
Wishing you all the best
Richard