I've never used TrustWallet, but I see they call it non-custodial and since you have a seed phrase it appears that it must be. At least partially so. Do you have to use 2fa to send a transaction? It can be email or sms confirmation codes, or a 2fa app, such as google authenticator. If so, it's likely that it's a 2 of three 3 multi-sig wallet already.
Say what now!?!? Where did you upload a private key? Did you upload your TrustWallet seed phrase? This sounds like a phishing attack!
PS; report anyone who sends you a PM offering to help, they're actually trying to scam you.
Thanks
I just derived the private key of the Tron address from a Mnemonic Code Converter ( https://iancoleman.io/bip39/ ), imported that key to TronLink Pro where it "told me" it's multisig as the TrustWallet was just asking for more Tron as fee.