Greetings weaam,
Clause 3.7.5 of which standard? Also, I do have to question if there is a possibility for you to review what information you ask for in your traceability exercise? Could it need a makeover?
I ask this because I have seen from time to time some "weird" questions which do fall under GDPR and yes they can be refused to be disclosed. I have done so in some cases too. Some examples are "Mention some of your clients", "Detail the cost of the raw materials used for the product you provide us", "Mention your raw materials suppliers", "Attach your company's legal paperwork" and other more or less similar things.
Point is I don't really know your questionnaire, but one must be careful when creating one, as there are things that are indeed confidential (eg names, cost values etc). The focus of this questionnaire must be solely to help them prove to you that they can trace their product with their raw materials and batches/lots and quantities used/produced.
It may not be the case, as you haven't provided many details, but I can't blame outright the suppliers. A smart auditor may also be able to discern if the questionnaire you use is too "revealing", but if he/she goes by the book then you will propably get an N/C.
Regard!