define a specific period for competitions and automatically receive the price after 7

Hi DesignContest stuff
firstly You must define a specific period for competitions. and also a time to choose a winner...for example, the other site of freelance without saying names maximum 7 days.. If the contest holder want to extend her competition it must also increase the price... because it is not reasonable to join in a contest for 15 days. and do a lot of change for the contest holder and in the last day it adds another 10 days or more... need to wait 1 month or 2 months to choose a winner. and finally do not choose you... It is not logical

and also when someone wins a contest. and there send the final files in the contest holder. need than the designer automatically receive the price after 7 days to send final files without the contest holder pay the price

and excuse me for my English and also thanks in advance