You didn't tell us the make/model of your own current phone but its unlikely you'll be able to do much with the keyboard, other than checking that it doesn't need a bit of a clean.
Of course, if its not that old, you may be able to get a warranty replacement.
You can order a new cordless phone with home delivery off www.amazon.co.uk, www.currys.co.uk, www.johnlewis.com etc. You MAY be able to get a local independent retailer to make a house call.
Hope that helps a ittle, September 2016