Is it legal for a finance company, over the phone, to say one thing and do another?

I thought I was only ten days late when I called GMAC to let them know when I would make my payment. They tell me that I had missed a payment and they had applied late fees (that I paid w/last payment) so in reality...I owed 1 1/2 payment I said OK. Called Mon. morn to have them do a draft....they don't do drafts...GMAC?......I had done a draft w/them before.....so I explained my banks policy concerning deposits. I told lady from GMAC that I couldn't get the money out till 4 that afternoon...I would immediately wire it in to GMAC no later than 4:15. They said okay.......20 minutes later my car was gone.