Haggling for new mobile contract

homer685

Interested in getting a 12 month contract with Vodafone (with Three at the moment) and I just realised that they do addons called passes. As having both the contract and one of the passes would be quite expensive does anyone know whether I can haggle with them when I go in the store to get the total amount lowered?

PS: I know I could trial and error this, just checking before I actually go there
PPS: Leaving Three as their internet connectivity in London is quite bad (Stratford, City, Canary Wharf, Oxford Street). Been a loyal customer for 5 years and had an unlimited package but the signal is simply ridiculous