The account was won following a five-way competitive pitch, which also saw Lewis PR and Racepoint Group vying for the business, currently held by Brands2Life.
Convergys provides outsourced customer care and billing services to businesses across the globe.
The company put the business out to pitch earlier this year (PRWeek, 13 July). Brands2Life will hand over the work to CC Group after working a three-month notice period.
CC Group is charged with working on UK and pan-European integrated comms to deliver a business rather than a technology-focused message. It is expected that the work will extend into the EMEA region.
The firm also wants to be positioned as a thought leader in the technology space, with plans to use Mobile World Congress as a platform to spread its message.
CC Group MD Richard Fogg said: 'Mobile World Congress is an important stage for Convergys as it has its heritage in the telecoms arena.
'The time we have there will be about lobbying for speaker slots and vying for award judging opportunities.'
The agency will work across telecoms, utilities and financial services to deliver an integrated traditional and digital PR brief.