Company Keeps Charging For A Service I Canceled A Year Ago.

Location: Massachusetts

Hello, I am not sure how to proceed, and I am looking for some advice. My family has owned a small pizza shop for about 40 years now. We recently canceled a service with a uniform company, and they have continued to charge us for the service even though it's been a little over a year since we canceled. We have been calling once a month to speak to the store manager, and he keeps saying that he will handle it, only for another charge to be sent to us (Keep in mind they aren’t even providing the service anymore). We have recently been sent mail by this company claiming that we have breached a contract and that we need to begin to pay them back, or they will get a collection agency involved. The thing is, we started to get this service when my dad first opened the shop almost 40 years ago from a family-owned business, and there was no contract signed between them and my dad. When the family-owned uniform business sold their business to a larger company, they kept us on as a customer and never sent anything for us to sign. When I spoke to the store manager, he stated that they have a contract and that we have to uphold it, and when I asked for a copy of that contracted he would either say that he would send it (He never sends it) or he would give me the runaround. I am not really sure what to do at this point, and I would like to know if the only solution is for me to get a lawyer involved to see this so-called contract that was signed by my dad.

(I do apologize if this is in the wrong sub and for my English)