No third-party service can forced-unban a permanently banned account directly from Riot's internal servers. If they claim they can hack the game to unban you, it is a scam.
If a service truly had a backdoor exploit to unban any Valorant account, they would face two economic realities: valorant unban service
If you believe you were banned by mistake (e.g., a false positive from Vanguard or your account was hacked and used to cheat), there is only one safe, free method: No third-party service can forced-unban a permanently banned