Unconfirmed BTC transaction / TXID doesn't exist?
In any case, receiver (Coinbase) can't do much to make your transaction confirm faster. Except CPFP, but you can do the same with your change output, if you have it. But, as mentioned above, if tx fee really is 0, it will not be relayed by the network, as default relay fee is 1 satoshi per vbyte. Also, in 7 days it should have been confirmed, as mempool clears out regularly at the moment. I bet you will not see that transaction by txid in any public block explorer either. So, you should just send them again from the wallet you initially send them out.