Sub-contracting : What if Vendor is not returning material within 180 days.

Dear MM gurus

I am facing one problem , when vendor is not returning material within 180 days , what is exact process to be followed in SAP. I know that duty amount to be reversed and material send outside to be scapped but how ?.

If i know that vendor will complete the process and will send material after 180 days then i dont want material to be scrapped . How to process it in SAP ?.

Thanks in advance .

VIJAY.