You sure can!
To repay a Spot early, just follow these steps:
Log in to Douugh.
Tap ‘Spot Jar’.
Tap the active Spot your wish to repay.
Tap ‘+ Make a repayment’.
Here you will be prompted to make your next repayment early and can just Tap ‘Make payment of …’ to repay the instalment with funds from your Spot repayment card.
You can repeat this step as many times as needed to pay back some or all instalments early.
You could even qualify for a bonus 4% Stockback™ by making sure you pay back your loan in full and on time.
Check out this guide on Stockback™ for more info: