If you have an F-account with Marsco (TradingFront's affiliated broker-dealer), you will have to call Marsco@+1 (877) 212-0588 for brokerage service. Or you can email support@tradingfront.com and we can coordinate for you.
If you have an existing F-account with Interactive Brokers, you will have to call IB@+1 (866) 694-2757 for customer service for that F-accounts and clients under that F-account. IB will not engage with questions on accounts under your F-account with Marsco.