Complaint sub-issue: Didn't receive notice of right to dispute

I visited a XXXX XXXX urgent care in XX/XX/2018. I paid a copay and did not know I owed any extra money. A few months later, I received one and only one letter from XXXX  Debt Collections regarding what I owed to XXXX XXXX  without receiving anything from XXXX XXXX in the mail.I then called to inquire in XXXX or XX/XX/2018and was told it was billed through XXXX XXXX when my current health care was and still is XXXX through my work. I let the woman know that there was an issue with insurance and that it was not correct since I was covered with XXXX. She let me know that I should have received an explanation of benefits from XXXX XXXX which I never did and that is because that was not my insurance and I never received anything from them. I proceeded to ask if there was interest on my bill or if I had time to figure this out to contact XXXX or XXXX and she let me know that nothing had changed to my total due and I said I did not feel comfortable paying at that time since it seemed wrong and confusing and as if there was a mistake with my insurance. I also asked for an itemized breakdown of the bill to provide to my insurance and more proof of this issue. I never received anything. 

I then in XXXX had another visit to next care for an XXXX attack and asked point blank if I had any outstanding balances or money I owed and they said no. I paid a {$100.00} copay that day. I never heard from XXXX Debt collectors again or next care. 

I then saw my credit score drop last week of XX/XX/XXXX and received a free credit report showing a delinquent report from XXXX Debt collectors on my credit report. I only received ONE letter from them about 6 months ago and only ONE call. NO other information I requested was sent or given to me. No other attempt to contact me and let me know it was about to go on my credit for 7 years. No other letters or calls about the situation at all. I am a responsible person. My credit score before all of this was put on my report last week was a XXXX and now is a XXXX. I have never paid a bill late until this situation due to the incorrect insurance issue. 

I called XXXX debt collectors and paid the bill in full and requested they take this off of my credit report and let them know that no one followed up with me and they claimed that through the record of our phone call that I never requested further info and that I said I would follow up with them which is FALSE. They never followed up with me about any of this. They refused to take this off my report which will now affect me negatively for 7 years. I have no track record of not paying my bills or owing them any money outside of this situation so I asked for goodwill forgiveness and they still refused even though I paid it in full within 8 months of this bill and no further attempts or warnings were made outside of 1 letter and 1 call. 

I then contacted XXXX XXXX and made the same requests as I did with XXXX Debt collections and they denied me and refused to take it off my report and claimed they sent the bill to me in the mail. They had the correct address in their system but I said " Since you never heard back from me and I didn't pay the bill, wouldn't you assume I did not receive it? '' They still refused to help me. It was down to he-said she-said ; even though I told them that I paid it in full they would not take this delinquent report off of my credit history. 

I then filed a complaint with trans-union and it is unknown if they will be able to help me. I am requesting since this is a first time situation and my bill is paid in full as of XX/XX/2018 that this delinquent report be taken off of my credit report due to lack of notification from the creditor as well as the debt collector. There was no contact since 4 months or so and was put on my credit report without any warning or final attempt as well as no adherence to my requests of further information.