I agree with John W. about using a more neutral term like "unreceptive." As written, the sentence sounds like you forced the customer to do something, which doesn't seem like a plus to me.

I would suggest splitting it into two, as it is a bit of a run-on sentence. 'One of my customers showed no willingness to move to the new business model. Though he objected, I was determined to achieve my goal and tried to convince them (him?) in various ways.' I'm also not sure what "convince THEM" is referring to. Are you trying to convince one person or several?

I am determined, in various way to succeed in convincing an unwilling and unreceptive customer who isn't opened to the new business model. Just my 2 cents worth.