Sent 1400$ to coinbase.com and Never received LTC coin

On December 4/2017 I sent 1,000.00 USD and bought 9.61949136 LTC and sent another 500.00 USD at same date for 4.81318346 LTC to coinbase.com but I have never got my coin and I wrote many email to their support team and called 3 times but no body has done any thing! I am planning to inform media and sue them because of my loose if they still keep to be calm about my issue.