Track Down Wallet

Sorry if this is a stupid question. This is my first post.

If a wallet is hosted online by a third party such as CoinBase or Mt Gox and I have that wallet address, is it possible to figure out which third party hosts it? I assume no, but figured I'd ask.

Back story:
I wanted to buy btc for the first time and wasn't sure which platform was the best to use, so I opened accounts with several of them on one day. I thought I was keeping good track of all my account info, but one of the platforms sent some btc I bought to a wallet I gave them, but now I can't find which platform is hosting that address. None of my new accounts I've checked have that wallet on record. I confirmed on blockchain.info that amount of btc I bought was indeed sent to the wallet they said they sent it to on the correct day. I just can't seem to find my wallet!