I've had my crypto's stole just a week ago from my Coinomi wallet. I searched all over internet for a safe wallet to store my coins. So I got wallet and held my coins there since Oct. 2018. After a few coins were stolen. I asked for Coinomi support for help with a ticket. Why don't they let people know of transaction threw email. I could have stopped it by changing my password. If I would have got info about this. Then other sets of coins came up missing? And still no replies. Sombody added ETH to my wallet and stole every coin I was holding. And coinomi says I got to use my private keys and passwords to send or receive coins which is a lie. I never needed private keys to move anything just my password. So I learned from my mistakes of holding coins in coinomi wallet. If wallet does not have a 2FA, Then my coins are not safe. But i'd like to report my stolen coins. I been tracking this one hacker that got into my google account threw there mobile IOS. And seen there from Cleveland Ohio. and would like to find them.
1. Coinomi is the kind of wallet where you have Full control over your private keys. Full control of private keys means full control of your money. They can't do anything to alert you or stop any transactions.
If you are careless with your private keys or (seed phrase) then that means someone who has access to them can restore your account from another device and withdraw anything from your addresses.
So coinomi has nothing to do with your money loss
2. The private keys and seed phrases are just used to recover/restore your account... say if you want to open it up in a new device. The password you set up on your account just helps you keep your wallet locked from any intruder who may have access to your phone. However, if a thief gets access to your private key. He will not need the password to access your funds.
He will just restore your account in another device as thou it were his and withdraw everything.
3. Like i said in point 1, coinomi is a kind of wallet where you have total control of your private keys and funds so it does not have 2FA. If a thief has access to your private keys, 2FA wouldn't stop him from withdrawing.
4. You device is probably infected with a malware that steals private information or you were too careless and gave a hacker access to your private keys. Basing on what you said, it looks like you kept your private keys/mnemonic phrases in your gmail, or google drive or google keep and the hacker was able to access it once he hacked your gmail.
It was your mistake not to enable 2FA on your gmail.