Is it normal to be doing assistant shifts without assistant pay?

Our store’s assistant deli manager quit about 6 months ago, then her replacement transferred to another store. I expressed interest in the position, and I’ve been training as assistant deli manager for 2 months now. I got 2-3 shifts training alongside the manager, and now they’ve just been scheduling me for normal management shifts on my own.

I’m wondering how long it’ll be before I get paneled and see my pay raise, and have been told they want me to go 2 weeks without any “issues” before they’ll schedule it. But it’s deli, there’s constantly issues. I spent a week as the sole manager when the deli manager was out sick, and still when she came back she was getting on me for not having worked a couple of cases from backstock. It’s starting to feel like I’m just filling this role so they don’t have to actually pay someone $19/hr to do it.