Answer
(Fatwa: 298/251/D=1431)
If you have given two talaq bayin to your wife in the presence of two witnesses, she became divorced talaq bayin. You will have to pay maintenance of the iddah period, if you have already paid it, you discharged your responsibility. Similarly, if you have already paid mahr, now you have no right of nikah on you. Her demand is un-Islamic and invalid. The abovementioned reply was written considering the content of question as true, if the wife has objection concerning any part of the details, or her demand is based on some other evidence, then the case should be raised to any Shariah Panchayat and get solved there.
Allah (Subhana Wa Ta’ala) knows Best
Darul Ifta,
Darul Uloom Deoband