The reason the amounts are duplicated is likely because of the field labels also containing the donation amounts. You can see this by editing the Standard Donation Level element.
  1. Fundraising > select Donation Management
  2. Select All Donation Forms
  3. Find your form and click Edit
  4. Click Design Donor Screens
  5. Click Edit next to Donation Form
  6. Select Standard Donation Level and Click Save Order and Edit Selected
  7. Look under the Label column and notice the amounts are typed in
  8. Delete/change those labels and click save