I have full access to my Google Account and I receive encrypted messages on my old delta account in phone witch i have not access because of accident. How can I get back the delta chat old account knowing only that my google account is linked to delta chat and recieve encrypted messages and not have access to old device to do (add device…)
Hello 
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is the old account a chatmail account?
If you don’t have a second device, account backup, backup of the key or full backup of the phone, then it is impossible.
In that case send messages to the people which send you the failed to decrypt messages to tell them that you got a new key, because you lost your phone, and they should resend the messages they send you.
When you send a message to other people they get your new public key so after that they encrypt to your new key instead of the old key.
If you lost the only device you had Delta Chat set up, you will need to setup a new Delta Chat profile.
Also change your Google account passwords, remove application password you have previously set up for the lost device and remote wipe the device if you can: