Bought house that had bonded pair service, how to request this service under new account?

I bought a house and had AT&T DSL installed. According to the online form, I can only get 3 Mbps. I talked to previous owner and he said he had bonded pair service allowing for 18 Mbps service (unsure if DSL or Uverse). When tech installed, I told him this and he saw that it was using two pairs previously. He couldn't do anything then but told me to call in and request it. When I called in the reps had no clue what I was talking about. How can I go about getting this service installed? I could REALLY use the speed increase as my kids are always online and this is my only option for internet access. Is there a different number to call so I can talk to someone who knows about this? Some sort of escalation team or specialist? Thanks.