Your case and question don't portray sincerity and it's incomplete at the same time. Is the wallet custodial or noncustodial? Do you still have crypto assets in it?
Based on these, if you don't have crypto assets in it, why waste your time, go for another wallet for privacy and security reasons. But if you have crypto assets in it and it's custodial, contact your wallet company with your original details for a reclaim. However, if it's noncustodial, signing a known message with your private key will be the most viable way out.
Let us make it maximum easy.
We both know seed-phrase. How can i prove that the wallet is mine???
Since you both are in possession of the secret phrase technically the wallet is no longer yours.
The best solution is for your to create a new wallet and let go of the previous wallet.