Freezes every time. – Runtastic Pedometer Step Counter & Walking Tracker PRO Review

I had this app for a while with an iPhone 5 and I could never determine if it was really all that accurate but at least it seemed to be in the ballpark and would count my time and distance. Now I'm trying to use it with a 5s and on my last 5 runs the app has glitched out each time and has stopped counting mid run. When I open the app I see it struggling to catch up and big chunks of numbers in mileage start skipping upwards. I've given this app so many chances. Restarted my phone, closed all other apps, etc. now I'm deleting it because it fails to serve its single simple purpose. Feels like a rip off to have paid for this.
Review by Heavy Boxes on Runtastic Pedometer Step Counter & Walking Tracker PRO.