Dissatisfied with service

we wanted our residential line transferring and were told that for a different exchange this would take 72 hours so we only requested the move on 1st February 2016 planning to be without a line for only a couple of days. tThe first installation date was 11th Feb (already more that 72 hours)when they came out a cable fault was blamed for no installation. Next was 8th March, they did nothing and said they would come back on the 9th which they didn't . Next date was 22nd March, No one came out, then 30th March and they didn't come out but they called and said there was a cable fault again. One call centre lady said that the cable fault was listed as having been resolved on the 15th February. it is now two weeks since they were last in touch and I try every couple of days to call the call centre only to be told the same thing \there is a cable fault\" I have an elderly parent living alone and need to be have contact urgently. I just want to know how long it will take but cannot get any higher than the call centre."