The girl's family, appealing to Prime Minister Imran Khan and Army chief Gen Bajwa for jusitce, said: "They are prepared to go to lengths" to ensure her return.
The girl, Jagjit Kaur, the daughter of a Sikh granthi from Nankana Sahib, was forcibly abducted and warned that unless she converts to Islam, her brother and father would be killed.
She is now known as Ayesha.
In a video doing the rounds of twitter, the girl's brother Dasvinder Singh says that a video doing the rounds claiming that his sister has been returned is fake.
"From yesterday a video has been running that Jagjit has been returned. That is a fake video, it is wrong news, nothing like that has happened.
"Nor has our sister been returned, or anyone been arrested for her abduction or conversion, and nor have we got justice.
"It is our appeal to PM Imran Khan and Army Chief and the Punjab government that our sister be returned and we get justice. If we don't get justice we are prepared to go to any lengths," he warned.
He also thanked all those who raised their voice along with the family for the return of his sister and were lending them support.
On Friday, India had said it has asked for "immediate remedial action" by Pakistan in the case of the Sikh girl.
India's Ministry of External Affairs in a statement, said it has received a number of representations from various quarters of civil society in India and members of Sikh religious bodies on the incident of abduction and forced conversion to Islam and marriage of the minor daughter of a Sikh granthi from Nankana Sahib, in Pakistan.
"We have shared these concerns with the government of Pakistan and asked for immediate remedial action," MEA spokesperson Raveesh Kumar said.
Earlier this week, Jagjit Kaur, who is now known as Aeysha, submitted her statement with a local Pakistani court under oath saying that she wilfully embraced Islam. She also refuted charges leveled by her parents on her abduction and forced conversion in their police complaint.
Another of her brothers Manmohan Singh had in a video related how she was forcibly abducted and warned by the kidnappers that unless she converts to Islam, her brother and father would be killed. "She was forcibly converted. It is my appeal to Imran Khan and Gen Bajwa to help us, and that my sister be brought back home. We apprehend that tomorrow such incidents should not take place on the Kartarpur corridor," he says in one video.
( With inputs from IANS )