Technically the Bitcoin can only be spent if you have the private key for the address. The private key is stored in a wallet. If you do not have access to that wallet then you will not be able to spend the money.
Try to contact the customer service of CoinBase to see what you can do with the information you have, also tell them if you have made any backups or wrote down any initial parameters (do not give away the exact parameters as it might be used to recover your wallet, just the fact that you have it or not).
In the comment below you mentioned they told you to never tell anyone the "Long"# you received, this is good, it is very likely to be a private key (about 51 random lowercase and uppercase letters and numbers) or some kind of "seed" (English words).
In case of the former you need to download a client and try to import that key. If you have the disk space (133 GB) I suggest using the official Bitcoin Core client, then after the initial synchronization finishes load your private key in the debug window follownig the How do I import a private key into Bitcoin-Qt? question. (Note: you are really likely to need to skip step 5 as your wallet is not encrypted.)
For the latter (if the "Long"# is a "seed") you need to use the same website/software you used when generated it but I really cannot help you out more than directing you to the customer service.