Selling a phone to a miner with no consent from a parent

My son and his friend on the 30th November 2017 .went to CNA to buy phone with no consent from parents, the store gave them phones and rica the phones with no information or documents from the parents. We went to the shop and were told that there are no they kids came with written letter there just do have copies , which is not the truth. we were also told by the manager that they can sell phones to anyone there are clause that says they can not sell to minors this is not alcohol were a child needs to be under the age of 18. I was also told by the manager that they can not be laid accountable . I was going to the shop everyday for the pass 3 day with no help at all