It can take several weeks for them to process the contract and then for Youtube to give control of ad revenue on your account to the network. Try opening a ticket/emailing after 2-3 weeks or so.
Which network did you sign to?
No need to open a ticket... Read every email RPM sends you, and do what they say. The next step is they have to sign the contract. They will then send you the finished contract. They will also send you a message to email to YouTube allowing them to partner of your account. It should take around a week longer.