I think "have been" is basically used to express an action that was started in past and is still happening up to present.
Now sometimes we use "have been" in the following contexts as well:
your device has been repaired.
The device was already repaired in past, so why am I using it to show the present context using "has been repaired"?
Can't I say "your device is repaired."
The past simple just talks about a past event, whereas the present perfect talks about a past event which is having an effect on the present. Saying your device was repaired only really says something about what happened in the past - it might still be repaired at the current time, or maybe it's broken again, but the past simple doesn't really imply anything either way.
Whereas the present perfect does imply the device is fixed right now, because it was repaired in the past - it ties the present state back to that past action. So it's very common for people to use the present perfect, just because of the sense oh "how things are, at this moment".
You don't have to use it, the past simple is just as accurate - but keep in mind that sometimes people can use that to be devious or misleading. They can talk about a past event hoping that you'll believe it has an effect on the present, when it actually doesn't (e.g. I cleaned the house, but that was a long time ago and right now it's dirty again!). By not using the present perfect, they're not technically lying and claiming anything about the present - but people will often notice this and get suspicious. "Why are you talking about the past, and not right now?"
I think you are conflating present perfect progressive/continuous with present perfect.
In present perfect progressive/continuous, "has been" is followed by an -ing verb.
He has been running.
In your sentence however, "repaired" should be viewed as an adjective, so your sentence has the present perfect form of "to be."
Your device has been repaired.
Your dog has been ill.
But you are correct that using the past simple instead of the present perfect is usually an acceptable substitute.
Your device was repaired.
Your dog was ill.
The difference is subtle.
For the sentence about the dog, "has been ill," suggests that the dog is still currently ill, while "was ill," suggests that it may no longer be ill.
For the device however, the two sentences are virtually the same (probably because of the implication that if the device was repaired, then it still is repaired). Personally, "has been repaired" sounds a bit more formal than "was repaired."
simple past tense (passive voice)- Your device was repaired.
present perfect tense (passive voice)- Your device has been repaired.
The present perfect tense tells us about the past and the present.
The simple past tense tells us about the past. But it does not tell us about the present.
Your device has been repaired. (It is all right now)
Your device was repaired. (It may be broken again now)
*present perfect continuous/progressive tense- He has been repairing. I have been repairing. We have been playing. He has been writing. The boy has been reading. They have been waiting. *
