I mailed a package by usps and it didnt arive to its destination.i paid for a return receipt with a signature?

i mailed a package on 2/11/08 certified mail and i added priority service, and delivery confirmation. its now 3/3/08 and the usps has no record of my package, the only record of my package is the two receipts i have. there are two different set on #'s on my receipts. my certified mail receipt has a diff set of #'s than my sale receipt. the day i mailed package i realized this as soon as i got home, and called the post office. they told me dont worry about it. when the package didnt arrive i called them back. they asked me for the # on the certified mail receipt, i gave it to them and they said there is no record of that #. then i told them the # on my sale receipt and that came up as a letter mailed to some place. i told them i didnt mail a letter. they said they must have made a mistake because the two #'s on my receipts didnt match, and they suppose to match. now my package is lost.i never received a receipt with a signature,so no one can have recieved it. what should i do next?

You need to go to the post office in person. If you got delivery confirmation, that number can be reviewed on the USPS website. I do that all the time. If the number does not show up on their website, something is wrong, but calling doesn't work. Go see them.