Hi there! I'm sorry to hear about the issues you're experiencing with your Myzone chest belt. It's great that you've already changed the battery and got a new belt. Let’s dig a little deeper to see if we can get this sorted out for you.

Can you tell me if you've made sure that the belt is properly aligned and snug against your body when you're working out? Sometimes, the positioning of the belt can affect how well it logs your workouts. Additionally, have you noticed any specific patterns, like if it fails to log during certain exercises or activities?

Here are a few steps we can try:

1. Check the Fit: Make sure that the belt is snug and not too loose. A loose fit can lead to inconsistent readings. It's often recommended to have the module positioned just slightly off center, usually to the left or on your back, for a better connection.

2. Connection with the App: Ensure that your Myzone app is active and properly connected to the belt. Sometimes, connectivity issues can disrupt logging. You might want to reconnect the belt to the app by restarting both your belt and the app.

3. Reset the Belt: If it’s still not logging, try resetting the chest belt. To do this, remove the battery and wait for about 5 seconds before reinserting it. When you put the battery back in, the belt should make a long beep, indicating it has been reset.

4. Monitor Accuracy: While you’re working out, check the app to see if it’s recognizing the belt and tracking your heart rate. Look for any error messages that might point to a connection issue.

If you've tried these steps and the issue persists, we may need to look into other possibilities, such as environmental factors, or contacting support directly for assistance. Just let me know if you have any updates, and I'll be happy to help you further!