How can my address could be wrong if i made all that in the "Exchange" field? If i was transfering btc to ETH, if for any reason the transaction fails, the money should return to where it started.
You can't send a bitcoin to an ETH address it should be bitcoin --> bitcoin and ETH --> ETH only. That's the reason why they said that they don't have a valid return address for you. They will ask for an ETH address where they will send your eth after they have confirmed your deposit so make sure that you have only entered an ETH address for that. You can double check it at your ETH wallet.
"Your pending transaction expired before we received your deposit.
Most probably they set a limited time for your deposit like for example, 1 hour, if they didn't receive the deposit within that time your session will expired.
Please note that in most cases they will require a certain number of confirmations before they consider your deposit valid. The mempool is currently overloaded right now so if you didn't sent it with a very high fee it might take longer to confirmed or worse might get stucked in limbo.
Well, i've contacted their support and the answer wasn't helpful: ""If it eventually is rejected, then the funds would remain at the bitcoin address they were sent from. The only thing you can do at this point is to wait and see if the transaction is accepted into a block. Like all wallet providers, Blockchain.info has absolutely no control over this, and cannot expedite transactions. This is always dependent upon the bitcoin network of miners, which we are not a part of."
Can you help me on this? What can i do to solve this issue?
Like what they said, Check if your transaction did really got included in a block. If it is, you can get a refund.
Paste the TXID here if its okay with you. I'll check it for you.