Whatever your contact says is legal, since you agreed to it in advance. What else does your contract say? I suspect your contract says you are entitled to 14 days in total, but only 7 consecutive days in one place. It's common in TT contracts to have a time limit of the stay in any one park and require you to move on before you can use the rest of the time. The reason is to avoid having the sites monopolized by longer term guests and giving other members a better chance.
My own particular TT contract provides up to 50 days total but no more than 14 in a row in any one park. Contract terms vary a lot depending on the deals that were offered at the time it was written, so there is no one standard set of terms & conditions.