No CPAP without an in-office sleep study?

I was recently diagnosed with Severe OSA for the 2nd time through an at-home sleep test. I've had a CPAP before but could not afford to continue to rent it. Now that I've had a new sleep study done, it shows my OSA is even worse than previously thought. However the CPAP provider said at-home tests are invalid, and I would need to schedule an in-office sleep study to prove I need a CPAP. I scheduled the earliest in-office sleep study I could, which is 2 months out. Why does this have to be so difficult?