Are you finding that when calling phone numbers that require you to use the dial pad from within the call, the numbers you press aren't being recognized? (Many times these are with 1-800 numbers or numbers with automated messages)
Below are a couple options where you can enable/disable these sounds in Settings:
From your dial pad (outside of Textfree)
1. Access your device's dial pad
2. Choose "Settings" from within the dial pad
3. You should see something similar to "dialer tones" or "ringtones and keypad tones"
4. Make sure the keypad tone is turned on
From your device Settings (outside of Textfree)
Settings > Sound & Display > Audible Touch Tones
Depending on the type of Android device you have, the Settings may be worded differently, but the same steps should apply.
If you find that these changes to your Settings still do not allow you to use the dial pad from within a call, let us know! We'll help out from there - send a message to firstname.lastname@example.org with the details