All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad, is His slave and Messenger.
Regarding your question about whether or not this marriage has ended, we say in reply: as long as this young man divorced her, the marriage bond is terminated, regardless of whether this marriage was valid or invalid in itself. We do not know what you find problematic so that you would ask afterwards, “After the ‘Iddah (waiting period), is the girl free to marry someone else?” Assuming that the marriage was valid and she was divorced and her ‘Iddah expired, then it is permissible for her to marry another man. If the marriage was invalid, then it is permissible for her to do so with greater reason. The matter is clear, unless you meant something else with your question.
It is worth noting that matters related to sexual intercourse are quite serious; the basic principle (default state) in this regard is unlawfulness, and such matters should not be taken lightly. Rather, the due conditions for the validity of the marriage contract must be observed when conducting a marriage contract, the most important of which are the consent of the bride’s Wali (guardian) and having two witnesses.
The Sharee‘ah prescribed these conditions to protect and safeguard the woman’s honor and dignity.
For more benefit on marriage through the phone, please refer to Fataawa 370909, 338692, 83629, and 133687.
Allah Knows best.