Sure! Here's the completed dialogue with the correct present simple and present continuous forms of the verbs:
Sue: Hi Deb. What are you doing (you / do)?
Deb: Well, at the moment I (1) am studying for the English exam on Monday.
Sue: Studying? I (2) never study on Friday evenings!
Deb: Well, I (3) always do homework on Friday evenings. Then I (4) am always free on Saturdays and Sundays.
Sue: It's a good idea, but I (5) feel lazy on Friday evenings. I (6) usually watch TV with my sister. She (7) always watches TV after school, but we (8) are not watching it this evening.
Deb: Are you (9) listening to music?
Sue: No, we (10) are playing a great new computer game. We (11) are phoning you because we want to play the game with you.
Deb: Well, thanks, but sorry, not now. I (12) am finishing my English book. What about tomorrow morning?
Sue: OK, that's great. See you tomorrow. Bye.
Deb: Bye!
Let me know if you need any further assistance!