Hey Debra! With these type of issues, it doesn't really come down to how fast your Wi-Fi is, but to whether it has the correct protocols enabled. As we are a VoiP company, there are certain SIP and UDP protocols that need to be enabled with your internet.
I would first recommend to clear out the app and update it if possible (in the PlayStore). After that, please reach out to one of our live chat representatives so we can conduct some tests, run diagnostics and get to the bottom of the issue.