Would you please speak into the phone as I don't hear you clearly.
Would you please speak into the phone as I'm not hearing you clearly.
- Generally, it would be "more natural" to say "I can't hear you clearly".
hear is a sense verb, like feel or look or seem.
- They are usually used in the simple present.
This coat feels good.
The soup tastes good.
The weather looks awful.
For something happening at the moment or for a voluntary action, the present continuous can be used:
I'm not hearing you clearly. [like the example above]
That's not sounding very good. [what someone says]
Here's a chart that sums up the uses of these types of verbs, which I cannot reproduce here. Please click the link:
There are also a few verbs that change meaning in the simple present and continuous: hear and see, for example.