There is unfortunately nothing you can do. Your post is not the first of this kind. Clearly you, or somebody with access to your account, was doing something Apple construed as violating its terms of use. They won't tell you what and what it says in the terms is somewhat vague.
Legal - iCloud - Apple
You can continue to use your software as long as you do not need to re-download it. Unfortunately the account credit is probably lost unless you can get to somebody high enough up the ladder at Apple who can override the standard operating procedure you'll probably get from the lower tier help people.
One concern is continued access to your hardware. Refer to How to remove Activation Lock - Apple Support for the various ways to remove an Activation Lock. If you have the necessary information you can do this yourself, otherwise Apple can completely reset a device if a person can provide sufficient evidence of valid ownership. Check the requirements and steps at: Activation Lock support request - https://al-support.apple.com/#/additional-support Apple says, "Proof of ownership documentation is required," but does not detail what currently constitutes proof other than it “must include the product serial number, IMEI or MEID.” Apple may typically require the original receipt* issued by Apple or an Apple Authorized Reseller. If Apple resets the device this will give you access to the device but won't restore access to the account used to lock it. There is nothing that can be done to expedite an Activation Lock request.
*Apple recommends you "Keep your receipt after you buy an Apple device" --> https://support.apple.com/HT202711
Of course then you're between a rock and a hard place as far as your software is concerned. if Apple resets your device then everything is deleted. You'll have to buy new software, though don't forget that all the basic stuff that comes with the operating system will be back on there.
