I read on wikipedia that the rambam had big מתנגדים סברו שיש בספריו דברי כפירה .Do you know who said it,and where its brought down, and what did he say ,that people should call such names?

ב"ה Shalom You question relates to an unhappy chapter in Jewish history which has to be studied at length. It was a controversy not just against the Rambam and the philosophy in Moreh Nevuchim, but against the study of philosophy in general and there was also those who opposed his halachic works in Mishneh torah. The controversy was in Spain and in France and it continued for a span of about fifty years after the death of the Rambam. There were those who put the Rambam and his writings in Cherem = excommunication and then there were counter excommunications. The zeal of those who opposed the Rambam eventually involved the Catholic church which did a burning of the books of the Rambam. But, Baruch Hashem the Rambam over the span of generations came out unscathed and his reputation lives for all generations, and all his sefarim are studied in great depth to this very day. Just to give you one reference where things were strongly worded against the Rambam, I can refer you to the letter of R. Meir Tudros Halevi Abalafia (הרמ"ה) in the book called ספר האגרות, also called כתאב אלרסאייל. (In a recent edition it is in ספר זיכרון בית אהרון , pg. 10, letter 9, where he strongly attacks the Rambam's view of תחיית המתים. All the best