My payment failed during checkout.

I hear a busy tone immediately.

The recipient’s line is busy or network is congested. Wait a few seconds before redialing.

Why do calls drop instantly after dialing?

Instant disconnection usually means:

• Incorrect dialing format (always start with +country code).
• Weak network or insufficient credits.
  Recheck both and retry.

Why does my call quality keep fluctuating?

Fluctuations happen if your internet bandwidth changes during the call. Close background apps that use data for better voice consistency.