How do you know for sure? Lol

Hi i had made a mining account on 50btc.com way back around 2-3 years ago. recently i had come across 74 bitcoins i mined withought knowing they even were worth anything. i had sent the payout to a bitcoin wallet on coinbase and it has not come through yet. i send numerous emails to 50btc and coinbase. coinbase responded saying that they have not recieved any transaction.  they sent me the block chain link https://blockchain.info/address/16ea9x9uiA6JpZN52TuiZ1H9bpbewS7Zkb and there has been no transaction for a long time. 50btc has not responded ive sent 3 emails and its been 1 week wait period between sending each email. I Am getting very fustrated because thats over $70,000 in the air. is there anything i can do? Can I have someone resend the bitcoins? Please Help.  Thanks in Advance!