Need help distancing myself from a friend.?

I myself had a friend exactly the same! I distance myself by ignoring all the calls and texts! It took a a good two weeks before i answered one of the texts and i kept it real short but nice about it! Told her i had been really busy with the kids and hubby and when i asked her how she was doing i knew i wasn't gonna get a good response i would say sorry Joey (my son) is getting into something we'll talk later! Its been a year now and i might hear from her once a month or kids birthdays! Her and I have been friends for over ten years too! But I definitely feel u on that note! Its tough but stick with it eventually she will get tired of voice mails and un answered texts!