Nedbank becoming the worst bank

I had the worst experience with nedbank, my account was blocked without notice...Used the app in the morning and evening l couldn't do anything even buying airtime. Went to the bank they said someone flagged my account and they are giving me a new card the following day 11 March with the same banking details,they couldn't do it on the 10th because the system was down to transfer money from my old card to my new card. Went back on the 12th to collect my new card only to be told my account is under investigation and they are trying to get hold of the person who flagged it and they are not reaching the person,money which was in my account was taken out by the bank and l asked what happend6of they continue not getting hold of the person,they said they dont know

So now my money is gone and l dont know what to do