Telegram Account Recovery Problem - Lost Access To Old Phone Number

I am writing to request help in regaining access to my Telegram account, which I can no longer log into on my Tecno Spark 20 Android phone. The account is linked to an old phone number to which I have completely lost access, so I am unable to receive the login codes that are sent via SMS or call. The problem started in October 2025, when I reinstalled the Telegram app and tried to log back into my account. Since the old number is no longer available to me, the usual login process has become impossible. I have not been able to use any alternative way to sign in, and I have not yet received any support because I have not contacted Telegram before this complaint. In the past, I set a password for my Telegram account (two-step verification / cloud password), and I still remember this password. However, I cannot even reach the stage where I can use it because the system first requires access to the old phone number. In addition, I have an active Telegram Premium subscription on this account, and I am concerned about losing both my subscription benefits and the account itself. I kindly request your assistance in helping me recover access to my Telegram account that is linked to the old phone number I can no longer use. I am ready to provide any necessary verification information so that you can confirm my ownership of the account and restore my access as soon as possible.