Not exactly sure what you mean. If you require tech support then naturally they have to have some kind of access to your system to help troubleshoot. For example to send a reboot command remotely, or see an error message that your system is giving.
That doesn’t mean that a Blink employee can watch the live feeds or recorded clips from your cameras. See the thread that @RightHand linked to, where @Bob_at_Blink explicitly stated exactly what I just said.
But if you’re uncomfortable with the idea of someone else having some type of remote management access to your camera system’s error logs or something like that, then the best way to deal with that is to not use a cloud-based camera system.