United States Postal Service [USPS] review: my package said that it was delivered but I never received it in my mailbox.

There was a package that was sent out to me from Narrowsburg NY . on February 12, 2016 through priority mail . I NEVER received that package .I received notice through text message on the February 17, 2016 that it was delivered .The package was never in my mailbox even though it said delivered . I was able to track the package from start through sorting mail then out for delivery that I never received .so from my understanding it went through the delivery process way after the expected delivery date .but to receive notice that it was delivered .the last person that would have handle my package would be the employee for the date of February 17 th 2016 at 4:38 pm .My package contained CASH money for my DISABLE daughter .she has MS for 10 years now and that was cash sent from a family friend to help pay for a new walker for my daughter . I had received one phone call message from the USPS . the number they left for me to return there call .no one ever answer the calls or it's always busy . I am assuming the worker on shift that afternoon saw that it was through priority mail and way past the delivery date . felt that the envelop was thick and put two and two together and realize that there could be cash in kept the package . my daughter can not walk nor write or anything else .if we can not depend on the USPS to delivered her packages with honesty then who can we trust . this is wrong and to not hear from anyone regarding the situation it's not fair .I believe the worker on shift for February 17 th at 4:38 should be spoken with .he or she was the last person to handle my package ...it was to be delivered to 320 Kingsborough 3rd walk Brooklyn NY 11233 apt 5E . in the name Shaqueina Elliott .Tracking number 9505511396046043586932 . PLEASE HELP . I know my package will not be returned i'm sure it's gone .but the worker should not be allowed to STEAL packages and clearly he or she has done this before .to allowed them to just get away with STEALING packages tells them that what they are doing it ok .and it's not .please and thank you ...Ms .Elliott