I hesitate to "recommend" a particular phone as your spec included M/S Office capability.
I think - but have not researched it, that MS Office 2010 includes a free web-app. If that is what you have (2010) then the world of Android might be your place to shop?
In which case, I have and like a Samsung Apollo. Much much cheaper than the i-whatevers, but has much the same in terms of functions. A smaller and less - pixels screen, but works well. Carphone warehouse sell it for £80 on payg.
Whilst carphone W are supposed to sell these phones on one network or another, both my daughter and I have bought Samsungs from CW and just put our own sims in. I suspect you need just a friendly manageress and a nice smile. Neither of the boxes had a network brand on them.