Bad service - delayed change of account name

Bad service - took offer an account from the previous person who stayed in the property I'm staying in. For the past 3 weeks both him (Mr T Gundah previous tenant) and myself (Current tenant) have requested for VOX to change account name from MR Gunda to my name but this has taken such a long time. As of today I called VOX and was referred to the sales team and spoke to Charlie Danster, whose reception was not pleasant at all.

Please assist that I get this resolved as I have to continuously call the previous tenant to assist. He has already done the best he can and sent all required communication for the process to proceed but VOX team is not helping.