Nicholas ngwenya unprofessional and rude behavior

These guys called me about a debt I have with absa Bank, I told the consultant at that time I could not speak coz I was driving and gave her a time to call coz I will be at home, the call never came, I got a whatsapp number for them and I made contact, and told them I would give them an appropriate time to call as I was at work,and we are not allowed to use cellphones, what followed is a very unprofessional, rude approach from them to such an extent that they told me to answer my phone..i told them i would not be forced by them to answer, I reiterated that I would give them an appropriate time to call.. They ended up threatening me with their legal department... I would like to state I will in no way be threatened or forced to answer calls when I cannot... These guys are purely very unprofessional and blatantly rude.. I have screen munched the messages for proof