You get what you pay for. First class mail is just one level up from the bottom afaik. Go for priority, express or even use DHL, UPS or FedEx to get it quicker with more tracking granularity.

About postmen walking away with your package: don't you think they'd prefer to lessen their load by leaving the package with you? Leave a note, saying you're inside. They probably are bored making judgement calls day in and day out, guessing whether people are at home asleep, in the bathroom, at the corner drugstore, away at work or maybe outaide queuing for a new phone.