We have a credit card, we simply always use a personal check as it is the most convenient for my husband, and we don't want to be set back by the credit card being rejected (Nor do either of us like making calls lol)
I don't quite understand, did you send your petition without any evidence towards the requirements? You are supposed to send quite a few things with your petition, which can be found on the official uscis I-129f website.