This sentence doesn't make sense like this, to use that you need an object in the sentence. If you want to say what the translation is (She has not heard from you.), the Italian version should be: "(Lei) non ti ha sentito." /Source: Italian girlfriend/
So does the participle "sentito" agree with the object (a single male here), if there is a "da te"?
I'm not sure, but I think sentito ends with an o, because the helping verb is avere, and usually the endings don't change if avere is the helping verb.