Object found in cereal

I bought a packet of All bran flakes, cocoa, almond, Oats cruch from Checkers. When I opened the bag I found a foreign object in the packet, it was a hard tube like plastic. This was a choking hazard, I removed it and packaged it separately. I immediately contacted Kelloggs and informed them, incase it's a batch issue. They responded asking for the receipt and my address which I provided. I told then that if they are collecting the cereal, to just please replace it and not send me a voucher as I do my shopping online, and going instore would be an inconvenience to me, for a error on their end. They arranged collection. I waited all day and no one pitched, I emailed them, and they rearranged only after I reached out. I emailed back to say that I handed over the cereal, and the object, but didn't receive my replacement. An agent called me and said I will have to wait on stock since I refused the voucher?! Then she goes on saying or I can take the voucher and just get me another cereal. I was so disgusted in the way they went out it. I told her, I'd please like my cereal and said they are being unapologetically unprofessional. She said, let me see if we can cash the voucher and drop your cereal tomorrow.. That was last weekend Thursday or Friday. Kelloggs this is pathetic! Especially since the tube couldve resulted in serious injury! Welcome to provide the reference number.