Canwood Base Camp Twin Over Twin Bunk Bed with Angled Ladder/Guard Rail, Espresso

We bought this about a year ago for our 2 sons then 3 & 4.5 and used the bottom bunk and a separately purchased trundle. My sisters 6 & 5 year old children had the bed and it was on her recommendation that I made the purchase. The bed looks great in the room and I was happy once it was put together. However when we went to move the little guy to the top bunk I had to convince the company through a series of emails and calls to sell me the straight ladder so that I could use the trundle once the ladder was installed. This cost extra $$. Where I'm disappointed in the bed is that from about the time our (now) 5.5 year old started sleeping in the top bunk the bed has become less sturdy and rocks whenever he crawls up and moves around in the top bunk. My sister's bed has never had this problem and hers is 3 years old while we've had it for about a year and I'm already trying to figure out how to stablize it. This is my only problem with the bed so just know that when you purchase it you may want to have a plan in place for making it more stable and if you have suggestions that would be helpful to me.

Bought these for my girls, they have had them used as bunk beds and separate twin bed. We love them. The color is great and were not too difficult to assemble, but help is definitely a must. Got the mattresses at Costco and saved there as well.