I have just received an invoice out of the blue from a company who provided me a service back in 2012. They claim they emailed the invoice to me back in 2012 but it was never received at my end. I am not disputing the invoice, but I didn't ever receive it. It was a few hundred dollars debt. I have never been contacted by the company until now, 4 years later. To chase up my email/computer records from 2012, I had to engage a computer technician to access the old hard drive of my old computer to try to find if the email had ever arrived (plus courier costs, et.c for the hard drive). I also had to pay the accountant to go through my old archived records from around that time to ensure that I hadn't paid it and forgotten about it, etc. There is no record of the email arriving and the invoice was not paid as I had definitely never received it. The costs to me to chase this up is more than the original invoice. My questions are: Can I "claim" the costs of chasing this up "against" their invoice given they left it so long to follow up? If they had followed it up straight away, I would not need to pay people to look up old records. (So if my bill is $400 for chasing it up, and their invoice was $300, can I ask them to call it quits and let the matter go? ) Or, do I still need to pay the invoice? Could I then claim against them for my costs and send them an invoice in return?