Could you speak a little bit louder?
Could you please speak slowly?
Could you please say that one more time?
Could you speak into the receiver?
A: I'm sorry. I'm having trouble understanding you.
B: I'm calling from the Mosocw office
A: Could you speak louder?
Did you say you want to meet on Monday?
A: Can I have your number?
A: Did you say two 5?