Nearly 800 jobs are set to be axed as Virgin Media closes its call centre in Swansea.
The telecommunications firm plans to reduce its number of UK bases from eight to four, centralising operations in Manchester.
A total of 772 jobs will go in Llansamlet, 552 staff positions and 220 sub contractors.
Virgin Media’s chief executive Tom Mockridge said the company planned to “completely exit” the site in 2019.
But Swansea council’s leader Rob Stewart said the company owes the city “a debt” and called for an urgent meeting to discuss keeping the jobs in Llansamlet.
The firm offers fixed and mobile telephone, television and broadband services to homes and businesses.
What was described as a “centre of excellence” for customer service and fault management opened at Matrix Court in the Swansea Enterprise Zone in 2012.
Swansea MP Carolyn Harris said: “I am absolutely devastated for my city and everyone who relies on them [Virgin Media] for work.”
She said the city had been “good friends” to the company and described the decision to move jobs to Manchester as “shocking”.
Mr Mockridge said the move was based on a decision to create “four regional customer services hubs”.
He added: “We are now working with and supporting all employees who have been asked to relocate, who may be in a role at risk of redundancy or who may wish to take another role with Virgin Media or one of our partners.”
Of the 552 customer operations roles, 470 will be transferred to the company’s Manchester base.
The 220 sub contractors are employees of Virgin Media’s on-site partner, Sitel, and these jobs will transfer to Glasgow.
Swansea council’s leader Rob Stewart called for an urgent meeting with the company to discuss how the jobs could be kept in the city.
He added: “We believe that Virgin and their contractor Sitel have a bright future in Swansea.
“But if we cannot get this decision overturned we will use a team Swansea approach bringing together Jobcentre Plus and our major employers such as TUi and Admiral to explore all local redeployment opportunities that are available.”
He called on the company to work with the council saying it “owes the people of Swansea a debt and therefore a legacy”.
Conservative South Wales West AM Suzy Davies wants the Welsh Government to help with support and retraining for employees affected.
Swansea West MP Geraint Davies called it “a catastrophe”, adding: “It’s a big blow for Swansea and means we need to work twice as hard to get more inward investment and get more jobs.”