I don’t know what they told Carter but they aren’t recognizing Israel’s right to exist. Just as everyone but the far left and Carter predicted:

“Hamas offered nothing to president Carter. They reiterated the same positions. There was no change on the part of Hamas,” Malki added.
[…]
Just hours later Meshaal told a press conference in Damascus that Hamas would not recognise the Jewish state and would insist on the right of return for 4.5 million Palestinian refugees.

(via)