My tenants did not pay the rent this month so I sent them a 5 day notice to pay or quit. I sent it via certified mail, but I did not ask for return receipt. The tracking information shows that that a notice was left, but its not picked up yet. How long do I have to wait before i can go to court, if they don't pick up the letter? Is this enough proof that I've sent the letter, or I have to deliver it in person too?