Quaziasim, there is no need to re apply at this point of time, i have seen some cases on forum with the same problem and when they wrote to CHC, they were sent the letters again. Send a case specific email to your local CHC explaining that you never received a letter asking for documents and show your concern that you are still desperate to immigrate to Canada. Post can be lost and it is international phenomenon and CHC is quite aware of that. They post the letter through normal post which has chances of getting lost. You will have to do this as soon as possible, write and send an email and also post a letter to them as well.