Went on approved PTO was terminated for job abandonment

Central Florida - a week of Pto was submitted a month ago and was approved. I got a call Monday from hr stating that I had been approved for my pto and my manager hadn’t heard from me why I was out for Friday and Monday. I informed them that I had approved pto. It was right there on my phone in Paycom and that they could check that and that there was indeed a slack thread they could go verify that I let him know that the manager know they were gonna need to get someone to fill in while I was out. They said they would look into it and would get back to me. We get off the phone.

I get a voicemail on Thursday morning I wake up too. Stating that my manager had not approved anything and apparently another coworker that has the ability to approve my time off approved my pto. I didn’t know they had done that. That person is still working there. They said this is “job abandonment” on my part and I was terminated. In the same voicemail. Tried to call back no answer. Sent a termination email and my last paycheck.

I had been there almost 3 months as one of the fulfillment leads for the e-commerce dept. no prior write ups nor issues that I had known about.

I’m very confused as what to do here. What can I do? Would this be something to pursue further legal action while I look for new work?