In the text chat credits are written off only after you send message or click start video button. E.g. if you have written a message to a girl and she answer on it, or, on the contrary, a girl has written you a message and you answer on it, 1 credit will be written off from your account. In video chat credits are written off only after clicking on the Satrt Video button (1 minute is equal to 1 credit). If the text chat is not stopped, it is automatically prolonged after 1 minute, just like the video chat.