Firstly, you should be focusing on applying to a subject, not a uni. If you focus exclusively on one uni then you are just setting yourself up for disappointment, whether you get in or not - I assure you, the uni will be more incompetent and less supportive than you could possibly imagine, no matter which one it is.
Secondly, the person lying about their predicted grades seems a bit unlikely because unis rely on the academic referee to confirm predicted grades. If they put higher predicted grades and the referee did not put those, it seems unlikely they would be accepted. So they may well simply have been given higher predicted grades in the end.
Additionally, even if somehow they did do that, getting an offer is just the first step, then they need to actually achieve it. More than that, after achieving the offer they need to actually do consistently well in the degree to come out with a 2:1 or above to have a worthwhile qualification in the end - even if we suppose they do lie and cheat their way through predicted grades and A-levels (very unlikely) the odds of them managing it for 3+ years is basically zero.
Thirdly and finally, if you were rejected in spite of high predicted grades, that indicates there is some issue elsewhere with the application. Your personal statement was weaker, you weren't taking a required A-level subject, you were taking a non-desirable combination of A-level subjects, if the course assesses GCSEs then you may have failed to meet one or more GCSE requirements or if you have poorer GCSEs this may have been an issue (possible for LSE or Oxford, unlikely elsewhere), if the course had an admissions assessment you may have done worse on that than others, etc, etc.
So you need to identify what went wrong with your application and then focus on either a) taking up an offer elsewhere b) applying through extra/clearing or c) taking a gap year and reapplying, all using the knowledge of what went wrong to see where you can improve. Obviously you should also aim to do as well as you can in your current exams for all cases too.