Learning from trustworthy scholars

I am a seeker of knowledge; I love to learn and I strive hard in the pursuit of knowledge. I am studying with one of the scholars (i.e., a Sayyid), leaning fiqh, nahw (grammar) and tajweed. Some of the brothers told me that these people slander some of the Sahaabah, and in fact I have found that this is true in some cases, but I am still studying with them. I hope that you can tell me which is best – should I complete my studies, or look for other scholars? I also wrote to the land of Persia, and they sent me some religious books and other material, but they are Imaamiyyah, i.e., they exaggerate too much about the Ahl al-Bayt (members of the Prophet’s household). Do you advice me to complete my studies with them? I read the Qur’aan a great deal in Ramadaan, but I found that I make mistakes in my reading. I went to one of the scholars and asked him to teach me, but I discovered that he makes mistakes, and I do not know what to do. In my area there is no haafiz, and during Ramadaan I stay in my village. Is it permissible for me to buy tapes of Qur’aan? or should I look for a scholar who can teach me Qur’aan?