You can still login to the portal and correct the mistake, but No correction will be accepted after the closing date.
So go back to the cyber cafe you did the registration and complain to them, then tell them you want to correct the mistake.
They would help you out,you would not be charged much.

Here is How to Apply for UNIBEN Post UTME Form.
The procedure for the 2019/2020 Admission Screening application is as follows:


Candidates are advised to have a valid e-mail account before starting the application process.


Visit uniben.edu
Click on Student Portal
Click on WAEUP Portal .
Click on Register for application at the top left of the displayed page to proceed.
Enter your Surname exactly as written on the JAMB Registration slip and your JAMB
Registration Number, immediately your ID and Password will be displayed on the browser.
On the WAEUP KOFA Student Portal click on ‘Login’ (top right of front page).
Enter your Username and password to login.
To start the application process, please click on the ‘Application record’ provide all required
information and upload your passport photograph.
Upload a RECENT and CLEAR “1 x 1” COLOUR PASSPORT PHOTOGRAPH WITH
RED BACKGROUND IN JPEG FORMAT ONLY. Great care should also be taken to
follow the specified formats on the UNIBEN website and portal. NOTE that the photograph
uploaded will be the only valid ID for all admitted candidates throughout their stay in the
University of Benin. FAILURE TO UPLOAD THE SPECIFIED PASSPORT
PHOTOGRAPH WILL LEAD TO DISQUALIFICATION and failure/forfeiture of admission.
To pay for the Application, click on “Add online payment ticket” at the bottom of the page, then
click on “pay via Remita” on top left corner of the page. Follow the instruction to pay the application
GROSS fee of Two Thousand Naira (N2,000.00) with a valid ATM-Enabled card from any
commercial Bank in Nigeria.
Preview and confirm your information before submitting your application online. (No
correction will be accepted after the closing date).
Go back online on the appointed date to print out the acknowledgement slip that contains
your specific screening schedule.
UNIBEN Post UTME Screening Exercise Schedule & Details.


GROUPING OF COURSES FOR SCREENING


1 SOCIAL SCIENCES AND ESTATE MANAGEMENT


Mathematics and Economics
Statistics
Social Sciences
Management Sciences
Estate Management
Engineering
Environmental Sciences
2 PHYSICAL SCIENCES


Physical Sciences
Education – Physical Sciences
Technical Education
Medicine
Dentistry
Basic Medical Sciences
3 LIFE SCIENCES


Pharmacy
Life Sciences
Education Life Sciences
Agriculture
Law
4 ARTS


Arts
Education Arts
Library and Information Sciences
Guidance and Counseling
5 OTHERS Special Education


Early Childhood Education
Adult Education
Candidates should go back on-line on Friday 2nd August, 2019 to check for their specific day, venue and time for the screening.


PLEASE NOTE THAT GSM PHONES AND CALCULATORS ARE NOT ALLOWED


UNIEN Post UTME Application Closing Date.


Application website closes by midnight of 29th July, 2019 (i.e. all applications must be concluded online not later than 29th July, 2019). Candidates, who pay after the deadline of Midnight 29th July, 2019 will not be screened.