Problems With British Gas

TCMUllane

Hi There 
  forgive me if this is in the wrong place 
i have a British Card meter still (not Smart Meter) i have around £500 on the meter 
 i went to top up the other day and noticed when i loaded it on to  the meter it said £3 debt £6
 gas
  i then called customer service as i should not be in debt with them been in the same flat 30yrs with British gas 
 and was told i owe £120 but they couldn't tell me why  they promised to look into it told me 48hrs heard nothing from them called back after 60hrs explained it all once again they lady on the phone kept leaving and coming back and still didn't get it resolved 
 they also seem to have on record that i have dementia which i do not and have never told them that
 they also say i have left and came back and i have not and that i owe them money from 2006 i have never had any contact from them regarding a debt or never entered into an agreement to pay a debt to them 
  any advice what can i do it sound like they got the wrong person and address