LONDON (Reuters) – Britain’s CityFibre has filed a complaint to the competition regulator against BT’s Openreach, claiming the nationwide network operator is using pricing to deter its internet service provider (ISP) customers from using alternative fibre networks. CityFibre chief executive Greg Mesch said: “We welcome fair competition, but BT Openreach’s behaviour is straight out of the playbook of a dominant operator using its market power and advantages to maintain its dominance. “If left unchecked, BT Openreach will strangle competition and threaten the pace of the UK’s full fibre roll out…