Unfortunately, we have not received the answer to our request and would be grateful to receive your reply soon.
It is now over three months since we placed our order and we have still not received our goods. I would like to point out that we have already paid your invoice and must insist that you deliver immediately.
Warning
Unless ...we will be forced to ...
If ...(not) ...we will be forced to ...
Unless we hear from you within seven days, we will be forced to taken legal action.
