the fact that Alastor knows what a 7-11 is, implies that not ONLY does hell have 7-11s in it, but they are SO saturated within hell, that Alastor can not remain ignorant to their existence.
That or in the Hazbin Hotel universe there were canonically a shit ton of 7-11's in the 1920's or earlier, considering Alastor was present during a stock crash in 1929 as mentioned in the pilot.
Let’s begin, I’m gonna make you wish that I’d stayed gone, tune on in, when I’m done, your status quo will know it’s race is run, oh this will be fun, muhahahahHAHaHAHAAAA