Saira, i do not have any experience with this standard, but i do have 9001. I looked it up and the 17025:2017 has 7.9 Complaints.
7.9.3 The process for handling complaints shall include at least the following elements and methods: a) description of the process for receiving, validating, investigating the complaint, and deciding what actions are to be taken in response to it; b) tracking and recording complaints, including actions undertaken to resolve them; c) ensuring that any appropriate action is taken.
and in 8.7 Corrective Actions, it talks about "
when nonconformities occur..."
Reading this, it does not expressly state that complaints are handled as Corrective Actions/Nonconformance's, but it would be a good avenue to take. CAPA's (corrective action, preventive action) are a great way to show that you have addressed the issue, and are striving to make sure that it doesn't happen again. It is also useful for tracking when a problem is recurring... then you can bring it up as a Risk.