If I understand your query correctly your problem appears to be:
You may be "requiring" a lead time of 5 days, but the subcontractor is telling you that they can't meet that.
They are asking for a 4-6 week lead time, which you apparantly can't tolerate.
So you want to continue using them, but punish them for being delinquent on delivery.
Why???
Obviously, if you are planning on continuing to use this subcontractor (instead of looking for one that can meet your lead time needs), then you are agreeing to receive and use the products when they are capable of providing them. I guess what I'm trying to say is, Are your "requirements" for lead time realistic and based on true needs? If so, look for a different supplier. If not, then get with your current supplier and work out a mutually acceptable lead time.
Afterall no matter what punishment you implement, your real threat is that you're going to take your business elsewhere (and when you don't your inaction is stating loudly to your supplier that you are willing to accept their process on their terms).