Blockchain wallets are public by nature so they can't be deleted or erased once they are on-chain. The only stored information you can erase is your contacts list. Follow these steps to erase a contact from your list.
We're sorry if we disappointed you in any sort of way, please feel free to let us know via our Support Center or via this feedback from.
Or were you looking to recover access to your Sequence Wallet account? Please follow the steps in this article: How to recover access to Sequence?