declined contract on incorrect information.

I went to open up a new line at mtn. Was told my application was declined because my credit score is terrible due to me not paying my accounts. I was highly upset because being a member or TransUnion I have my credit details and my credit score is fine till this date. At the time I did not even get a report from TransUnion to notify me that there was any enquiries on my profile. I called the call centre and was transfered to pillar to post and finally I was told to sent through my TransUnion report to them as proof that my accounts are not listened. Never in my life have I been so degraded and embarrassed. Mtn needs to tell me where do they get their information from. If they want to me sent them the report I will do so but I want to know where do they get their report from.