My account was fraud when I refused scam they put in disconnect

I did not disconnect my service. When I hung uo on target scam they out ina disconnect for my service. How did they have access to my account. What do I do I do not want my service disconnected. I called security line but am not sure why they couldn’t resolve immediately. 
I tried the online chat and they said I needed to add service which the same service is almost double what I was paying please help