Filed I-751 on Dec. 20th to Texas Service Center. Noticed the next day a new form and fee ($275 instead of $205) on USCIS website (supposably new ed. since 08/06, but not showing on website at time of my filing). Sent a check for $70 and a letter explaining this the next day on Dec. 21, as someone in the same situation had done on this forum. Got my check back on 01/03, with letter saying that due to large volume, fee can not be matched to application already in file and must be accompanied by new application...I am assuming that my application went through with the "old" fee and am still waiting for NOA with a GC expired since 01/03...