Denied refund for service not provided

Hey folks, wondering if anyone has any insight on this situation.
I purchased a membership for 3 months from a company. 1 month into my membership there was an accident of some kind and the company had to shut down for repairs for the remaining 2 months of my membership. As I needed to keep this service going in the mean time I went with another company that provided the same service, and took a membership with them.

Now that my membership with company B has expired, and company A is back open I returned to them as I preferred their service. I went in to inquire about purchasing a new membership expecting to have the 2 months previous deducted from the cost. They told me that they had already given me extra time compensation (when they reopened) that I did not use, and this is my tough luck.

I'm no expert but I assumed I have to explicitly accept their form of compensation and since I didn't I am entitled to a refund now (approx 9 months since original membership), however I'm not sure now after reading citizens information. They mention that not acting immediately can be perceived as acceptance of their offer.

I did ignore it because I kind of thought, oh I'll just keep up my new membership at company B and when it finishes I'll go back to company A, and I imagined they'd be happy to have me come back but apparently not, and now I might have screwed myself out some money