Translation:Your eyeglasses will be repaired on Monday.
Spectacles is also a word. Why do people keep downvoting this. I'm sure spectacles are never used in some places but - then again - in others it is. Stop downvoting comments with correct suggestions!
I'd think "Your glasses will be repaired by Monday" would also be correct. The meaning of the clause is not that nobody will touch the glasses before Monday, it is that on Monday, they will be in a repaired state.
Frankly, it kinda sounds like they won't be touched until Monday. Your version is "do poniedziałku".
But as it's only "kinda sounds", and it's also possible that they will be repaired on Friday, I'm adding your version.
The future passive is full of mistakes or incorrect translation. This sentence should have been translated like this: your glasses will have be repaired on Monday
"will have been", if anything.
But actually 'w poniedziałek' almost certainly means that someone will repair them exactly on Monday, not before.