I would like to inform you that EPFO may be asking for a copy of Form 5, which you have already submitted to the EPFO. Currently, all employers are submitting their returns online only. In this case, there is no need to fill out Form 5.
I believe EPFO may be requesting Form 5 for the period before online submissions were implemented. In your message, you did not mention the specific month and year of the Form 5 that EPFO is asking for.
I have also attached Form 5 for your reference.
Thank you.