The head of the WTA has threatened to pull events from China if Peng Shuai is not found.
The Chinese tennis star has not been seen or heard from since accusing a former Chinese state official of sexual assault on November 2.
Peng said she was coerced into sex at the home of Zhang Gaoli, one time a prominent member of the China's Politburo Standing Committee. Her post on Weibo was deleted half-an-hour later, and she's not been heard from since.
Naomi Osaka, Serena Williams and Novak Djokovic have been among the major stars to call or Peng's safe and immediate return.
Earlier this week, WTA chairman and CEO Steve Simon received an email - claiming to be from Peng - which disavowed the accusation against Zhang and said she was safe and well.
However, Simon said the email served only to heighten his concerns over her wellbeing.
He's since claimed he's willing to pull all tournaments from China, unless Peng is found safe and well.
"We're definitely willing to pull our business and deal with all the complications that come with it," Simon told CNN.
"Because this is certainly, this is bigger than the business.
"Women need to be respected and not censored," Simon added.
He said the WTA have been in contact with counterparts in the Chinese Tennis Association, who have given assurances that Peng is unharmed and in Beijing.
However, Simon said, "We have reached out to her on every phone number and email address and other forms of contact.
"There's so many digital approaches to contact people these days that we have, and to date we still have not been able to get a response."
The Chinese Foreign Ministry was not able to provide an adequate update on Peng's whereabouts on Friday.
Spokesperson Zhao Lijian claimed that the matter was “not a diplomatic question and I’m not aware of the situation.”