Lack of service

Just over a month ago a technician came to my house and changed me to a different exchange as he said it was more stable. Every week since then there is an outage on that exchange. I work from home and if I have no Internet I do not get paid. I was told by the call centre that the sales department can put me back to the old exchange. Called Sales and they laughed at me saying they cannot do that. Also when I call about the outages, your faults agents tell me they cannot log a fault as the technicians are already aware of the outage. I cannot afford to keep losing money. Please put me back to the old exchange