Over charged and poor service

This company has been ****ming me since when I signed up with them, i took a package of 20mbps and I have never seen that 20mbps instead I get the lowest shamelessly speed of between 2.5 to 6.1mbps , everytime I called them its like I'm talking to the robots they all say the samething (I'm sorry we will escalate) since from the 2nd of February till now they still escalating. I've tried on a numerous attempt to talk to account and was told they will escalate, tried to asked for manager and told no manager but they will escalateto Team leader. What a shameless disgusting service they have daaaamn, if you been promised to be called that's a lie