Yes it’s right - but if you worded it “Thanks for acknowledging, I completely understand - these things happen!” it sounds more “natural”. If you want you can add “my email/message/text” (or whatever it is) after “acknowledging” to sound more formal. Hope that helps!

It is correct. A less formal way would be: Thanks for acknowledging, I understand. Things happen sometimes. A casual way would be: No worries, noted. Talk to you soon! Hope this helps, Jojo! :)

This is correct. However, its register is mixed, formal and informal. In a formal context I could suggest: Thank you for taking the time and effort to apologise. I understand that some things are beyond our control. Hope I have helped!

No you can’t. We just don’t respond that way. First of all it is a statement which is often left just acknowledged but not necessarily responded to. If you feel like responding to it, you can just say please don’t worry about your late reply, it can happen to anyone. For the future reference- in appropriate scenario- it is better to say thank you for your / the acknowledgment… Hope that helps 🙂👋🏼