Problem with my WordPress site since my SmugMug free trial expired

I had set up a free trial for SmugMug to see if it could work with our WordPress sites portfolio page. I have since decided to go about it manually since I can’t find a good SmugMug plugin that suits my needs. However, now that the trial has expired, I get the message below, no matter where I go on my WordPress site (I’m logged in as the admin). I didn’t deactivate or delete the SmugMug plugin I had installed, so I assume it’s generating an error now that the trial has expired. The error message I get is below.

SmugMug API Error for method smugmug.albums.get: expired account (Error Code: 25)SmugMug API Error for method smugmug.categories.get: expired account (Error Code: 25)SmugMug API Error for method smugmug.subcategories.getAll: expired account (Error Code: 25)

If I’m not logged in to my WordPress account, I get a paged cannot be displayed message. What are my options to get around this? I have contacted the plugins developer, but haven’t heard anything back.

Since I can’t access the plugins area to deactivate and delete the plugin, would it be possible for me to manually remove the plugin by accessing the folder for it on the server? Would doing so cause more problems?