How long am I allowed to stay under section 3c? Is it 14 days after the refusal or 28 days after the refusal?
You get 14 days to apply for AR. if you do not apply, they will return your documents and then your section 3C ends.
If I make a fresh application, my section 3c ends and does that have any effect on this new application? Would this fresh application mean that i won't be given the right to apply for admin review in case they decide to refuse my application this second time?
No as long as you apply within 28 days of your section 3C ending. So you get almost a month to apply for your new application. You will not lose your right to AR but be aware that your new application needs to have all the documents and satisfy all the requirement to make sure you get the extension 99%.
You do not get any other chance after that as the 28 days will be over by then !
Advice is given based on my personal research and experience only. Do NOT contact me via private message for immigration advice