Mycelium has an "Accounts" tab on the left, check if it has more than one entry aside from your main HD account.
Thank you so much for your response. I only have one account, I tried it on different wallet including the Mycelium Android app and they keep showing the same balance different from what I have on the iOS app. I have tried everything possible, Mycelium will tell you your funds are safe but you can't access your funds with the seed you were given. This is so frustrating.
This complicates the issue.
It seem as the wallet has been showing addresses that aren't derived from the BIP39 recovery phrase.
And the send issue could mean that it doesn't even have the private keys to properly sign the transaction when you're trying to send.
You could still try Electrum's "
Detect Existing Account" button during BIP39 wallet restore to see if it's somehow in your second+ 'account_index' but it's failing to show it in the original client.
If no other result but the first one with transactions 5 years ago, it could be a bug in their outdated IOS client.
Sadly, it's 'closed-source' so they are the only one who knows if there's an issue with their code.