Poor purchase security measures

Im so disappointed about the security of payflex. My payflex account has been compromised they purchased with 2k without my knowledge and they also added their bank card details on my payflex, and i have been trying to reach out to payflex with no availability. I request payflex to cancel the order immediately because i wont pay for something you dont know. You are deeply disappointed about the security of payflex. How can someone add their bank card and buy with your account without security verification. I immediately phoned tekkie town store where my account was used and was told to contact payflex but all their communication platforms are not reachable