Make sure you are not creating a hard point in the wire (stress concentration) when splicing it back together. If you do chances are you are going to have it break there again after a while from the flexing.

As for the your cable getting to short .... Just splice in a piece of telephone wire. Or replace the whole wire with the phone wire. That way you eliminate all possibe problems with the wire you have now. Phone wire is cheap. Small gauge speaker wire will work too and it is stranded (and as such will flex better) unlike the phone wire which is not stranded.