DISRESPECTFUL CALLS FROM ABSA EVERYDAY ON MY PERSONAL PHONE

I am receiving more than 15 calls a day and when I answer the call they drop on my ear. I even received an SMS saying that Absa is trying to reach out to me about maintaining my vehicle. I am not even sure where did they get information that i need their services regarding maintaining my vehicle. This is so frustrating and disrespectful because you can't call a person and drop on their ear when they answer. I even spoken to a guy today 27/05 at 08:55 his name is Given and i asked him how would he feel if something like this is done on him ? I AM TRULY HARRASSED BY ABSA VEHICLE SERVICES and it must stop!!