i don 't get the 300 points ???

I have my account for serveral weeks now but have no updates whit 300 points every ten days???

It's because you already have enough points to submit translations. With the number of points you have, you can submit nearly up to 600 characters to be translated. We only give points to people who need them (negative number of points).
The goal of this system of 300 points is to offer hte possibility to everybody (including people who don't speak a foreign language) to use cucumis but I don't want that the people who don't translate get more points that people who translate a lot