Lost Exchange Account
Man, maybe the answer will shock you, but... your amount of crypto is probably lost.
I say ''probably'' and not for sure.
the options may be 2:
1. the transaction was too small, so miners didn't pick it
2. it's fault of the exchange
I don't suggest you to use coinbase, I suggest you buy on spectrocoin -> https://spectrocoin.com/en/ 
And to trade from crypto to crypto using Binance -> https://www.binance.com/?ref=16821839
Anyway here's a guide to choose the best exchange -> https://medium.com/@bitfinexed/coinbase-insider-trading-litecoin-edition-be64ead3facc