@KM. Brother they have not lost your documents. 99 times out of 100 they don't lose any document. And I know you are not that 1 unluck person. I was also afraid for my documents, I had sent my educational, property and company documents but nothing happen to my docs. You just email them and ask for the suission of your deferral letter. Don't take much time. Do remember to put your file no, date of birth and passport no in your email.
If you need any other advice just inbox me your email.