Weird transactions, statement and missing bank notifications

A lot of unusual things have been happening in my account this past month.

1. I do not have a credit facility on my account but I went to sleep with R907 in my savings and woke up to -R907(again not credit facility). I transferred money into the account and the -907 was cleared. My balance was around 4000+ I got a refund of over 3000 and my new balance was 5700.00. I went to the bank to ask what was going on and I was told I had purchases reserved. I am very careful with what I spend and when you swipe that balance is moved from your Available to Balance. The bank notifications show the money was moved from my savings to the 'reservation" or whatever. No one is telling how I suddenly had a negative balance and why my money has been disappearing. The 3000+ refund(I never got a notification) and there was a time in the last 2 weeks were I didn't get any real time notifications and suddenly I have all this happening in my account. No one wants to help me, I get generic answers and no investigations. Also by the way there are transactions not showing in my account but I have the email notification of it which is very *****.