Landlord Opened Mail Addressed To Me And Attempted To Cash The Check Inside

State: Arizona I have my rent checks mailed to me from my bank every month and then personally drop them in the leasing office mailbox (because of a repeated pattern of incompetence on their end that I won’t get into here). But the 1st of this month rolled around and I hadn’t seen my check come through my mailbox yet. Assuming it got lost in the mail again and not wanting to be late on payment, I hand-wrote a check and delivered that one. A week later, I get an email saying my check bounced and I will be charged a $50 fee along with my January rent next month. I open my banking app and see that not only has the check I delivered gone through, but the money is gone from my account and I had sufficient funds for an entire second check still left over, so it wasn’t due to insufficient funds. There are also photos of the check that show it was stamped and such as deposited on their end.

So I email them politely stating all this and sending the screenshots. In response, they literally just sent their own photos (no message or further explanation) of the check that was supposed to have been mailed to ME but they somehow got ahold of it and tried to cash BOTH CHECKS and then charge ME a fee because one of them bounced!!! (because obviously I was smart and canceled it)

I was hoping they would come to their senses after I provided the evidence of my on-time payment and remove the fee, but lo and behold, this month’s invoice hits my inbox and the $50 fee is incorporated into my amount owed. So I printed all the email exchanges and photo evidence and folded my check for this month (sans fee) into an envelope and dropped everything into the mailbox. Despite this, I get yet another email today telling me I “need to pay the full amount” on the invoice. I wanted to rip my hair out!!!!

Their behavior is borderline harassment as this point (they also send security guards to bang and yell at people’s doors late at night who have “missing payments”) and it feels like they’re purposely acting obtuse in order to squeeze more money out of me. I was thinking of at least reporting them to the USPS for opening mail that was addressed to me. But can I legally (or otherwise) do anything to escalate it further? Thank you in advance!

TL;DR: My apartment complex tried to cash two rent checks for the same month, one of which they got by opening mail addressed to me, and then tried to charge ME a fee when one of them bounced. What can I do?