TikTok Account Log In Issue

I am a TikTok user from Nigeria and I am writing because I have been unable to access my personal account, even though I still know my username and password, and I need help from TikTok support to recover it and update my contact details. The account I am trying to access is @ritabarbara***. I originally registered it with an email address and phone number that I no longer have access to. Some time ago, someone else used my account without my knowledge to purchase TikTok coins and send gifts during live streams. As soon as I noticed this, I changed my password to secure the account. After changing the password, I was logged out and, when I tried to log in again, I was asked to verify using the email and phone number that are now long lost. Since then, I have not been able to log in properly. For a while, until about last week, I could still access the account via Safari on my iPhone 8, but I was not able to change the email address or phone number from there. I then changed my username and assumed I would be able to search for it in the TikTok app and recover the account more easily, but after that I could no longer log in from Safari at all and I still cannot find or access the account through the app. The access problem originally started a few months ago, after the password change and verification request. I have already contacted TikTok support and tried to use the forms provided. I was asked for details such as the last device I logged in with, the sign-up date, the city and country I registered from, and the device I used at sign-up. I provided the information as best as I could remember, including that I am currently using an iPhone 8 and that I am located in Nigeria, but my problem has still not been resolved and I remain locked out of the account. I kindly request that my identity be verified through alternative methods instead of the old email and phone number, and that I be allowed to regain access to my account. I also request that my contact information (email and phone number) be updated to my current details once my identity is confirmed, so that my account is secure and such issues do not occur again. I am ready to provide any additional information or proof TikTok may reasonably require in order to confirm that I am the legitimate owner of this account.