That was the problem I was having around here. I couldn't find a dive shop or a business with a compressor that would pump to 4500 PSI. I ended up ordering a compressor and SCBA tank. It's a big expense but I shoot a lot and needed it when I needed it.
Found a dive shop in Knoxville that can fill to 3000 psi so that will do for now. Hoping to talk to our local volunteer fire department to see if they can help. Just have to drive by the firehouse at the right time.
As my budget allows will invest in my own compressor and be done with it. I hate depending on someone else for stuff like this.
PS: purchased a carbon fiber tank with 98 CF capacity so will be set for awhile.