Bullying company

I was contacted by this company telephonically years ago. I have a small business and agreed to try out their cartridges which were sold as generic but good quality cartridges. I felt sorry for the call centre lady who was polite and persistent. The cartridges were posted to my post office and paid for. What followed were a number of years of harrassment from the call centre insisting that i have a contract with them to supply me with cartridges. Over the past 2 years they have phoned me every few months badgering me to take more cartridges. Finally in a state of frustration and exasperation i agreed to take a set of cartridges to just get them to leave me alone. I asked the sales person if this was possible and he agreed it was. I have had this reassurance before so i was sceptical. When i received the cartridges, i asked if i could have a letter to confirm that i would no longer be harrassed. I was assure by Christopher in "accounts closure" 10 days ago that i would be emailed my letter as soon as the money was in the bank. I then paid. And waited. NO LETTER. I have just received another call from Stratus to say i have to buy more cartridges according to the contract. I HAVE NO CONTRACT!! I then contacted "accounts closure Christopher" who then told me that he cant close the account because of some order that was never collected in August 2016. I plan to take legal advise over this harrassment.