Arresting for payment that's not mine

Good day I am very irritated with Hartman Attorneys I have mentioned to them time over time and that I don't any one anything my son is almost 18 and he was at H F Odendaal in 2018.I always get this messages and my son just attended this school for the first term in grade 8 so I owe nothing to this school I spoke to pretty today when I called in and she just plain rude said I'm at legal and I must pay while u was talking she dropped the call they are very unprofessional I have send whats apps to the number provided in the message but they just ignore me I am really tired of this people arresting me. THIS is the message they send today.We have send out tracers to confirm your adr. We proceeding with LEGAL ACTION for FH ODENDAAL ***, R8508.5 HARTMAN ATT ***....How can I owe that school if my child did not even finish the term Hartman Attorneys Tel: *** ***