A friend of mine (person A) has had his resignation retraction denied because a replacement (person B) has already been moved (without Person A knowing). However this isn't true, as Person B was notified 2/3 weeks prior (whilst they were on furlough, and wasn't informed they were a replacement for Person A). Whereas notice wasn't given until last week - and wasn't intimated previously.
I understand that a company can reject a retraction without giving a reason, but as they've said that Person B was coming as his replacement, could this amount to constructive dismissal?
Related: The reason for retraction was because the branch is being transferred to another company under the same group, and following discussions with them they want to remain. However it is the previous company that are denying the resignation retraction.
Are there any employment laws being breached, or is it just one of those things?