for your guidance it helped me. If they don't give me more time then shall I submit the fees caz if I got visa so its good but if don't then they will charge me 500$ for refund.
Yes refund is always an option. I faced a similar situation to that of yours (last year and this year as well) so I contacted my university. They said I could pay it after my deadline (23rd Aug) but I'll need to see the Admissions officer in person with the proof of payment, before Sept 14th, so that they could manually register me to my courses. The faculty is very helpful and always keen to guide you so don't leave your problems out when interacting with them. Insha'Allah you'll get your visa. If not (may Allah forbid), you'll have to request them for a refund, like I did last year.