May 10 (Reuters) -
* CMA says Capita and Vodafone face an in-depth merger investigation, unless companies offer acceptable ways of addressing competition concerns.
* CMA's initial investigation into merger found it could lead to a substantial lessening of competition in supply of wide-area paging services in UK.
* CMA says after merger, customers could face price rises and reduced quality of coverage.
* CMA says Capita has until May 17 to offer proposals to resolve competition concerns or face an in-depth phase 2 investigation. Source text for Eikon: Further company coverage: [ ] (Reporting By Simon Jessop)