Foreign Object found in Doritos package of chips

Early in January 2020, my son was eating Doritos from the party packet size of chips. As he was chewing on the chips, he chewed on something hard. When he retrieved the hard object from his mouth we saw that it was a metal stud. The sort of metal stud that is found in jeans/pants. My son is receiving orthodontic treatment and wears braces. One of the studs that was on his molars fell off as a result of biting into the metal stud. Simba customer care was very efficient in arranging the collection of the packet of chips and the stud. Post collection, I have not heard from Simba and they do not answer my emails. My sons orthodontist has billed me for replacement of the stud. This incident was no fault of ours. Simba pls reply!