Market complaint regarding

I have a one question suppose i am a customer purchase xyz company medicine found major defect found so im registered the complaint against the XYZ company
So regarding to market complaints investigation detail company send to me or FDA?

In case of any market complaint related to the product quality or packing or any adverse reaction etc the customer has right to inform about that complaint to the manufacturer (pharma company) along with complaint sample or its photograph as a proof (supporting document) and preferably invoice / bill of pharmacy shop from where he has purchsed that product (with batch details).
The manufacturer (pharma company) investigates the complaint, verifies the genunity of it and sends reply to the customer (complainant).
If similar type of complaints of the same product and for the same batch are received from different customers and if the complaint is of critical or major type then the manufacturer has to recall that defective batch from the market and inform to FDA about the product batch recall. Manufacturer has to investigate in to the matter to identify the root cause(s) of the complaint and inform to FDA and all customers about CAPA actions taken.

Therefore, in your case manufacturer should acknowledge the receipt of your complaint and send you the reply about the cause of complaint and what action he would take. (If your complaint is valid)