Gathering to offer Salah and leaving dissension

Q: Dear Shaykh, we are writing to request a Fatwa (legal opinion issued by a qualified Muslim scholar) about a matter that many Muslims suffer over the city of Jilak, France. On the 27th of Ramadan, in 1994, the Muslim committee decided to close the Masjid (mosque) due to a misunderstanding between us and them. The matter remained the same until ‘Eid-ul-Adha (the Festival of the Sacrifice), when the Masjid was opened again and we performed Salat-ul-‘Eid (the Festival Prayer) there. After around three months, the group that had separated from the Masjid decided to hire a hall to perform the Five Obligatory Daily Prayers. Few days after that, the regular Imam came to the main Masjid and contacted us, asking to return to the Masjid. He promised that he would be with us and the other group equally. Despite all these attempts, we have not returned to the Masjid. It is worth mentioning that the Masjid is never a quarter full; only 40 people at most perform Salah there and the area of the Masjid is enough for 100 people or more. A little while afterwards, we brought an Imam to lead us in the daily obligatory Salah and also the Jumu‘ah (Friday) Prayer in the place we hired. (Part No. 6; Page No. 288) However, after a while, we discovered that the Imam we brought writes what he calls: "Cure for people" (i.e. amulets), and takes fees for this.The question is: Is it permissible to perform Salah behind a person who writes amulets and preservers? Is it permissible to perform congregational Salah in the place that we hired, despite there being Al-Masjid Al-Jami‘ (the large mosque where Jumu‘ah [Friday] Prayers are held) that is not full on Friday. Many people are still asking us to return to Al-Masjid Al-Jami‘. As-salamu ‘alaykum warahmatullah wabarakatuh (May Allah’s Peace, Mercy, and Blessings be upon you!)