My partner has a Holden Barina and we had to change the battery. Now the CD- Radio does not work.?

We have tried to re- program it with the code but nothing. This should be easy I believe, the player itself says 'enter code', so we do and nothing. I have searched the web for answers but I have found the same questions as I am stating here. I have rung Holden the dealer and they can re program it for a cost. There must be an easier way surely?