Big Easy complaint: Not up to standard

We had originally booked the Covent Garden branch, where we ha e been numerous times and always had a great time, but our booking got redirected to Canary Wharf due to Covent Garden closing at short notice.
It was our 20 year anniversary and we really wanted a special evening and this really wasn’t.
Our food arrived cold, we told the server and it was taken away. My husbands food came straight back as they said said there was another one that had been made but I had to wait for my food. The shrimp was over cooked and tough and it really put me off the rest of my food. We weren’t made to feel like the evening was a celebration so we decided to leave as really wasn’t enjoying our meal.
To top it off we used the toilet on the way out and they were in a shocking state. The 2 available cubicles had used toilet paper everywhere and hadn’t been flushed and one had a big roll of toilet paper on the floor that was wet a d looked like it had been dropped in the toilet. Clearly no one was checking the toilets. I took photos. This really made the evening worse.
This is not what I would expect from the Big Easy.