Good Character

Q: I got mail delivered at home and on the envelope the stamps were unstamped. Is it allowed to use these stamps to send mail?

Q: I had another question that has been bothering me recently. I did my medical school in my native country. I am an old graduate of medical school and I have started PhD in public health in the US from this summer. It was possible to enrol into a PhD program because the university offered me a full scholarship for PhD. The only thing I regret is that for admission and scholarship to the university, I lied on my resume and personal statement that I was the best student in my class during medical school but the transcripts and recommendation letters submitted were completely authentic and the university also verified them by requesting a sealed official copy. So the lying was only on the resume and personal statement. But maybe it was overlooked by the university and they gave me admission and a full scholarship. After I enrolled myself in the PhD program, the Program Director has introduced me twice in various meetings that I was the best student from my country. Now I feel that my troubles are because I lied to get the admission and particularly the scholarship and that has now resulted in Allah giving me multiple problems in my career. I cannot inform the university about this or the Program Director who gave me admission and scholarship as I do not want to be labelled a liar but I want to know how do I repent for this sin to avoid any troubles because of this. The other issue is that I have circulated my CV to my advisor as well and other post-doctoral fellows with this lie and I would have to continue doing this for the next five years because I now cannot change it if they ask for my CV again. Kindly advise in light of Islamic teachings because my only intention was to get admission and a scholarship and was not to harm anyone by this. 

Q: The law of pension is that the individual must not have any means of income. Can a pensioner conceal the means of income and qualify for the pension? The pension form is filled and signed under oath. Can a person apply for it under these circumstances only in order to cover taxes?

Q: What exactly does it mean when we are advised not to concern ourselves with that which does not concern you? For eg. my husband is going somewhere and I ask him where he is going to?and why? etc. Am I wrong to be asking questions? How do I prevent myself from bothering over useless issues like these?