A fiance(e) visa is valid for maximum 6 months.
During that time you will be expected to actually get married and after marriage to submit an application for Further Leave to Remain (FLR(M)) in UK as a spouse. The visa granted will allow you to remain in UK for a further period.
Unfortunately you will find it extremely difficult to contact UKBA by telephone.
I wish you luck with that.
The UKBA website you need to start at can be found here
The page explains how to apply for permission to remain in the UK as the partner of a British citizen or a person who is present and settled here, if you are already in the UK in a different immigration category.
The form you need FLR(M) and the guidance notes can be downloaded from the links on the right-hand side of the above linked webpage.
For contact to UKBA please see this webpage
