You already have one HWID registered to your account, and the free allowance for DST VAG IMMO Tool 4.0 is for one device. Since you formatted the device and the previous key no longer works, I can issue you a new license for the same HWID you originally registered; this does not consume another slot.
If the new HWID you just submitted (CA7B2-F574C-E5BA6-61349-7EF87-615DE-DF2EB-8D0BE) belongs to the same PC after formatting, post your original registered HWID and I will confirm whether they match. If they match, I will regenerate the key. If the hardware signature changed or you are activating a second machine, you will need to upgrade your account to Stage 1 or higher to increase the device limit.
What was the HWID you originally registered?