Ah...too late. I called them and gave them my mobile. If the tennant did take out a loan and I am a liable to pay for it then I will but does it usually take 7 years to contact someone?

Hello, First post here so not sure if it is in the right forum! I just recieved a letter from a debt collection agency for the first time ever. They say I owe a loan company 250 pounds from a time I took out a loan in 2006. The address that they have is one that I was once living in but moved out some 7 years ago. The loan is for 250 pounds and I can easily pay it but I have never once taken out a loan in my life. The house I was living in was rented and I think that the other tennant may have taken out a cash loan in my name. I am awaiting paperwork to get to the bottom of it but I fear this could happen again as I have not spoken to the other tennant since way back then. Do debt agencies usually take 7 years to start tracking things like this down? Any advice would be appreciated!