Most teachers are very professional.. But I've seen HTs behave in the same manner, as Roomba said. I also had a HT accuse me of fraud when we paid our dinner money by cheque, which was cashed, and then she accused us repeatedly of trying it on with regard to getting free school dinners.
I kept going in with my cheque stubs and bank statements to prove it had been paid. That was not enough for her. She demanded the bank get the actual physical cashed cheque from its offsite storage facility to prove it had been cashed. (We are talking £40 here). Bank were incredulous, nobody asks for cashed cheques for such trivial things, apparently (it's a village, they all knew her). I told her this and refused to comply, saying she had the information she needed and she should double check her own records.
This went on for a few weeks until it came to a head and I stood in the school office and said 'The leadership and management of this school leaves A LOT to be desired' in a particularly withering way, which caused her to more or less melt down. So yes, things got heated. I am sure if I wasn't a senior figure in education, she would have claimed I was being aggressive or something and got her attack dogs to escort me off site as well. These weaker HTs think they own the school, quite frankly. Little Hitlers, they are.
After the Local Authority got involved, it turned out the school office had made a mistake in the records by not entering our name against the payment and consequently the council had put the £40 down on a separate budget line on the spreadsheet. Because she was a complete turnip she was not able to realise the two amounts of money - the unallocated budget line and the amount of the cashed cheque - corresponded to exactly the same amount of money, which meant the money had been found and the mistake was at their end.
I never got a sorry and in fact she never missed an opportunity to get the knife in after that. I pulled my kids out of the school as there were lots of other things she was getting wrong as well, from the teachers (and indeed this very woman) frequently not showing up for work because their absence policy was a mess, to my child getting a broken limb because she didn't think it was necessary to supervise 210 mixed age children outside at lunchtime, so all the teachers were in the staff room having a nice cup of tea when an 11 year old grabbed my reception age child, held him upside down and bashed him against the slide to see if he would cry.
Not a well run school. So never assume it's the parent until you have the full facts.