Mweb - impossible to get hold of

My daughter who resides in the UK has been battling to get hold of Mweb to cancel her account. I took it upon myself to visit their premises to hand in the cancellation letter. Mweb moved from N1 City to Century City. I drove to the new premises only to be told that they have moved from this place as well. The problem is Mweb have my daughter's old mobile number on their system so calling them is fruitless as the "agent" simply states " we cannot take your call at the moment". it is the most frustrating exercise trying to speak to someone to process her cancellation