W810i SMS using more than one message?

[heirpin]

Hi, excuse the ignorance, I'm an old git so not really well up on these things but whenever I send/reply/forward a txt, quite often, it takes two or sometimes three messages and as I'm Pay and Go, its costing me!! So, I was wondering if there's some setting I need to adjust?

..also, I received a txt from a shop today and although I don't have their number in my phone, it came up with the shop's name, presumably, I can do likewise with some setting somewhere?

..and one last question - if I purchase a Pay and Go phone locked to say Vodaphone can I then get it unlocked at my local 'unlocker' so I can use it on my O2 Sim (this is way cheaper than buying a phone free to any provider)?

all help/advice much appreciated!