I don't use SBI, but the email looks like mentioning about account opening charges that is charged by some brokers such as Zerodha.
Nevertheless, never depend a single broker. Always use at least two brokers. Things can go wrong. When things do go wrong, we need an alternative broker to switch holding so that we can sell them if needed.
If you haven't seen any issues with your current stock broker, you have been just lucky.
Every broker has some issues that may not affect everyone.