Inappropriate conduct from Mahlatse from FNB secure chats.

Mahlatse from FNB secure chat ended a conversation whilst I was still talking to him /her. He/She decided to send me a chat that suggests that no communication was received from myself which is not true. Instead the opposite is true as he/she is the one that was not communicating continuously.He/She even apologised for responding late to my chats. I chcked on him/her 2 times as he/she just vanished.He cannot dismiss me like that. Supervisor must please check the intervals between out chats and explain to me when did I not respond or continue with the chat to prompt Mahlatse to end the communication just like that.