First, you have to know the reason why she doesn't want to get back with you. If the reason is justified, it will be hard to get her back. Sometimes, when people decide on something they never look back.
Stop any communication with her for a minimum period of two weeks., and then contact her afterward. If she responds during the no contact period or responds positively after ending the no contact, then you'll have her back in your arms.
You should take your time to reflect on the broken relationship, and change what might have led her run away from you. You shouldn't force her to come back with frequent calls and texts. You'll only aggravate the matter as you'll turn out as bothersome or irritating. Give her some space then contact her after a period of time.