Bharathiar University — Payment issue

I am Megha and a student of Bharathiar University SDE. I am doing MCom CA and my first year exams are coming on December. All the students were asked to pay the examination fees before 30 Nov
On 27 November I paid their fees through their site and my money got deducted. But it was not reflected in the site. It was again asking me to pay the amount.What to do now.