lost my entire transfer
don't know if this help 
but I had the same problem 
COINBASE FIX IT 
sent btc to my coinbase receive address but I did not cover the fee>> fee amount to low .
2 1/2 week went by it showed pending on coinbase 
blockchain showed no transaction completed.

it first show back in my personal wallet 
then a week later coinbase shows I received btc 0.000685 btc 


  
    I sent 0.3555000
    but 1 week later it pulls from my wallet and goes to coinbase in full.
    so coinbase did something on there end to push it through.
    I was out nothing . 
    but it takes 3 to 4 weeks for them to fix it .
    hope it help you