my antminer mines since 3 days...but i didnt get any payments to my bittrex wallet...

Last LTC block was found 4 days ago. So that is your problem. You only get paid for the blocks that you help to find. This is how mining works in reality. Smaller pools take longer time to find a block, but logically the reward for your shares for the block is higher than on a larger pool with higher hash power. Over a long period of time, this more or less evens out and rewards reach equilibrium. On a shorter time frame, variance can swing the expected reward from the mean, meaning you can be either under-rewarded or over-rewarded.