There's no reason why the appearance of the AOL brand name should be connected with any service problems you're experiencing.
'TalkTalk' is a brand name of Carphone Warehouse. AOL UK used to be owned by the American media giant, Time Warner, but 16 months ago they sold the business to Carphone Warehouse. (So AOL UK and TalkTalk are effectively the same company). At the time, Carphone Warehouse said that they'd keep the two brand names separate but it seems that they're now looking to link the two brands. However there's no reason why 're-branding' should affect your level of service.
http://www.webuser.co.uk/news/97311.html
Chris