if i were you i would return the phone under vodafones 7 days returns policy, and get one online or from Carphone Warehouse as their phones are all unlocked.

yeah a reflash might work but thats a hassle and risk IMO.

Vodafone are an excellent provider but their customer services and branding is a real problem, i remember seeing a N95 branded Vodafone, they removed the radio access and wanted you to sign up to their paid internett radio servies.. tut tut...