one sends notice to another in an Envelop actually putting notice in it, but other side giving reply that he got empty envelop(for just buying the time or whatever may be reason). My First question is what to do in this matter, one simple answer may be "send another copy" but I want to know if there is any other answers. My second and most important question is what should a person sending notice do at the time of sending notice, so that after getting notice, if one denies, it can be proved that notice was sent in envelop and it is not an empty envelop, in another words how can it be proved that notice is actually sent and it is not an empty envelop, what to do at the time of sending notice so that even if after getting notice, it is replied that envelop in an empty one, it can be proved that it is not empty one.