leoo2107 wrote:
- i cannot go for administrative review because of my HR mistake..
In the refusal letter have they not given you the right to apply for AR?
Most of your questions have been answered by others.
Has HR emailed UKVI asking for urgent treatment of the CoS allocation request on the basis that your leave expires on 17 June?
If you are not allowed to request AR and your visa expires you can stay in the UK for 28 days after the visa expiry date but you will not be allowed to work. Overstaying by not more than 28 days will not affect your re-application if you make it during this "grace period" . Hopefully the allocation will come through and the CoS will be assigned during this period.
The UKVI service standard for processing unrestricted CoS allocation requests is 18 weeks but in practice they usually come through in 2-4 weeks.