Refusing Shipment Letter

[Name, Company Name & Address here]

[Date]

Dear [name],
I want to inform you that I am returning back the shipment of [product name] we received last week.

We cannot accept the order no. [no. here] because [state here the reason].
I want [state here the possible solution – change in the product]

Please advice us when to expect the new shipment with the changes described above.

Regards,

[Your name & Designation]

[Company name]