How to send a contact letter to the construction party for the property with falling ceiling?

It may be caused by unqualified construction.

Contact the construction unit first to inform the contractor that it will not perform the warranty, and then send a letter to the contractor. The content is very simple, that is, dozens of words: according to the quality guarantee of commercial housing, how long is the project warranty period? Our company requires your company to fulfill its warranty obligations. Please send someone to our company for consultation and rectify the maintenance plan within a few days. If the time limit is exceeded, our company will contact other maintenance units to carry out engineering rectification, and deduct relevant expenses from your warranty fund. Ask the construction unit for the other party's contact address and telephone number, then send a letter to the post office and EMS, indicate what the rectification contact letter is on the mailing list, and then keep the receipt and save the circulation information of the mailing list number on the Internet.