Bad and dishonest company

I am with Standard Bank for the past 20 years and open savings accounts for my two children also a few years ago. Now my two children's accounts were frozen due to no activity in the last few months. I only deposit money into these accounts. No withdraws were made, only deposits, I keep the cards and only I have the pin. They are underage and have no access to these savings accounts. I try to deposit money, but the accounts do not exist anymore. I send an email to Standard Bank and visit the local branch, no response. I now consider changing to another Bank. Standard Bank is pathetic and *******, to say the least. The interest rate is high and the client service is of the worst I experience.