This is none of my business but was there any other unfavorable info on you during your probation period. (Late, problem in training, argument.) Coming from a former HR position myself- that would be the first question I would ask.
It almost sounds like someone in management had it in for you. All you have to do is p#ss someone off- which you know- is pretty easy.
The bottom line is PRIA. Any problem you had will turn up in the records report. You may want to request your PRIA records and get a written reason for the situation.
Now here's the weird part. On future apps will ask "have you ever been fired." YES or NO. Technically you have NOT been fired. But there's a lot of gray in that statement.