Need help lost parcel with USPS

[superek4]

A parcel was sent to me on 5 or 6th march but till today 5th April nothing has arrived I email usps but no reply the sender said he called but usps can't help also.

What can I do? It has 2 esc n 1 medusa motor inside.

The tracking no is lc534976460us but it says accepted not send out of US. this is the first time I lose a package.

I have brought so many stuffs from US never lose before. What's going on? Can anyone help?