A deposit transaction and a membership upgrade transaction are two different things. Even if there are funds on your account, you will still have Free Membership until you upgrade to a paid membership plan.
An account’s membership can be upgraded immediately if there is sufficient account balance to cover the membership change. Otherwise, you will be asked to deposit funds to your account to proceed with the upgrade.
You may refer to this article for details about making a deposit: How to Deposit Funds to Your Freelancer.com Account
Once your deposit reflects on your account, you may then proceed with upgrading your membership.
Should you wish to change memberships, you can do it anytime by going to the Membership page. Just click on your profile picture at the top right part of your Dashboard and select Membership.
An important thing to note is that membership plans will automatically renew after the paid period (30 days) in order to save you the trouble of upgrading each time the paid period ends. So make sure to keep track of your membership plan's start and end dates to manage your membership plan efficiently.