We apologize for the inconvenience caused, as per the description above, you are not able to see your signature on the PDF file when the other user sent it back, Is that correct?
Please check for any pending updates of Adobe Reader from Help>Check for updates.
What type of Signature did you use in the PDF which you sent earlier? Is it possible to share the document with us so that we can verify at our end? To share the document, please refer to How to share a file using Adobe Document Cloud