Anonymous account default for 2007 listed on my credit report in August 2017

I would like to know how this on earth such an inhuman act out of nowhere can really be added onto my credit profile without my knowledge. I called TransUnion sometime this month wanting them to provide me with a credit report. The agent told me that I have a default listing for an account that was defaulted in 2007 under Calton Gym. The ID number on the profile doesn't even belong to me. This is not the 1st time I am experiencing issues with Gym company. the last time I checked someone, I do not know how decided to use my bank account for their monthly subscription. I had to throw tantrums to the big bosses for the issue to be resolved. For the sake of progress, I have called their accounts department and requested to pay the default so they clear off my profile on the 8th of this month. Still until now I have not even received any confirmation of the progress of this issue. I regret joining this gym last November and would like to terminate my membership ASAP. I am just sickand tired of Gym Company....