HaGaon HaRav Bentzion Mutzafi Shlita in a Shu’t released which addresses one wearing a sheitel (פאה נכרית), the prominent Sephardi posek rules that one should not buy tefilin from a sofer whose wife wears a sheitel for in his view, it is tantamount to the wife being without a hair covering. The ruling is published in ‘גביע הכסף’, where a number of halachic questions are addressed.
The rav adds that if a Sephardi girl attends seminary in England and she is asked to wear a sheitel for a shidduch, she should not accept the shidduch. The rav was also asked regarding the psak of HaGaon Chacham Bentzion Abba Shaul ZT”L, Rosh Yeshivat Porat Yosef, who is matir the sheitel in his sefer Ohr L’Tzion. Rav Mutzafi stated Rav Abba Shaul was never matir a shteitel and he never wrote such a psak in his sefer.