Call centre phoning me but all I get is silence when answering

I have been receiving spam calls every day for more than a week. When I don’t answer my cellphone then the work landline rings. I can’t take calls during working hours. The worst is that when I do answer then I hear the call centre in the background but no one speaks and eventually the call is disconnected. Please take me off of the phone list! Today’s phone call was from number O*** at 11:48 and I was kept on the line for over a minute with no one speaking to me.