Free Traffic Legal Advice

So as the topic say I stupidly took advantage of my blue badge by reporting it lost 2 times to get 2 new ones and use all as I have 3 cars in my household and I can get free parking with it. I park all cars at the same area. Few days ago I went to my cars and the one with the old blue badge had a PCN on it. The anti fraud unit has written to me asking for details. The blue badge unit also sent me an email asking me if recieved my badge. I have not replied to either one. I’m panicking because I feel not only have they discovered the invalid one but maybe they have been able to connect the two present at the time of checks and just waiting to disclose it all to me when they get me in for an interview under caution. I do not want to make mistakes going forward so any advice would be helpful. (I am aware what I did was wrong & definitely not here to look for pity) I accept full responsibility and just looking for some understanding of how things are likely to proceed.