French phrase
Je vous ~ mal.
Meaning
I can't ___ you well.
When to use it
The other person's voice is hard to hear. Polite and common on calls when the volume or connection is poor.
Example dialogue
Allô, c'est Marie.
Hello, this is Marie.
Je vous entends mal. Pouvez-vous parler plus fort ?
I can't hear you well. Could you speak louder?