You need to make up your mind.
So did you, or did you not dismissed her.
You say you made a mistake and it should be maternity.
Then you go ahead and say you want to dismiss her.
She can't take maternity forever. So she has to be back by the date stipulated. Otherwise she must resign.
You can't dismiss someone just because they having a kid.. If she does not return to work after the stipulated period, then you can dismiss her. Will probably not even be necessary if she ignores your messages. Wait for the time she haS to be back. If she does not return for work, send her a message. If she ignores the message. Send her another message as a last warning. After that, take HER to CCMA
What is the result from the SAPS case?
Something tells me you are going to need a lawyer to help you sort your the case of theft and get a proper investigation going.
If you are 100% sure it was her and you have valid proof. She is in trouble anyways.
As much as the law makes it more challenging to unfairly dismiss someone, this is one of the reasons why the law is needed.
There is more to this story.