Transworld Systems sent me a letter indicating they collecting a medical bill debt. I believe I have paid this bill and attempted to call their customer service number multiple time. There is no answer -- only a strange message about an extension number. I logged on to their website only to find there is no way to dispute this debt on the website. They provide the same phone number described earlier. 

This also happened to me in XXXX 2014. I still have that issue on my credit report. 

This company makes it difficult or impossible to contact them.