Forced to pay full deductible before claim was submitted and payment not showing up on bill.

I underwent a procedure a few months back and was told I would need to pay the rest of my deductible ($1,492) at the provider’s office that day since they were not sure if my insurance would cover any of it. I was extremely concussed at the time so didn’t think anything odd of it, but in hindsight I should’ve protested. Now the bills are flowing in and the bill from that provider does not show the amount that I paid on the date of service and after my insurance payments the total amount I owe is significantly less than what I was charged in office on the date of the procedure. I have a receipt of the payment I made in office that date, but it does not say what it was for, just has the date and the amount I paid and the procedure, site, provider, and description columns are all blank. I’ve tried calling this office’s billing department multiple times but it always goes straight to voicemail and they say they’ll return calls in the order they were received but it’s been 2 months and probably 10 voicemails I’ve left and still no response. I didn’t have my HSA card the day I had the procedure done so I paid it on one of my credit cards. Since the billing department hasn’t responded to me, I’ve resorted to filing a dispute for this charge with my credit card company, to which I’m told they are accepting the dispute given the evidence I’ve provided them. I believe this to be an error since the $1,492 I paid already isn’t accounted for anywhere on my bill and I was told that number was specifically to max out my $1,500 deductible (the only claims I had on my insurance prior to this procedure totaled to $8). Any help is appreciated to shed some light on this and hopefully get me my money back.