Problem scheduling my HSG test

I have PCOS so I have a period every 39-46 days, it’s at random and I don’t know in advance what it’ll be since that’s already 7 days in between. Well everytime I go to schedule an appointment they don’t have anything and tell me to call again next month because my appointment has to be scheduled 7-10 days after the first day of my period.

I have called 5 places, with the last almost being an hour away. I’m desperate. Help!!