incorrect details cant be resolved without putting yourself at risk

i am receiving messages that i have unpaid loans with FNB, so i call the number provided and explain the problem, the consultant asks me for my identity number, i rep**** that i am not happy to provide my ID but will gladly give her my cell number as this is were the texts are being sent to , and also protecting myself as the next thing i will be billed for someone else's loans. the response i got is not what i expected, she cannot help me as they work on identity numbers only. so why am i receiving messages for something i am not responsible for ?? clearly its okay to open an account and provide an incorrect cell number as long as you have an identity number.some other person can be embarrassed for an unknown account!!!!!