By the way, I found myself in a similar position to you just a couple of weeks ago.
I bought a website with pre-paid banners on it, and the previous owner told me that the banners were due to expire within a week or two. Actually, they were already paid for a further 9 months.
Ignorant of this, I just removed them after two weeks and put in my own affiliate banners. A few weeks later I got a couple of emails from the sites which had purchased those banners, asking where they were and telling me that they had paid up to $1000 for them.
I replied and told them that it was not my responsibility and I had purchased purely the domain and content, and not any business or accounts.
They both said “fine, it’s not your problem” and I didn’t hear from them again.