Why are my products not importing anymore on my trial account?

I was exploring and adding products to Shopify trial. I made several small csv’s. Products were successfully being uploaded. Once it came to Product count: 4964, the imports after that did not import products evern after saying that the products have been imported. I tried adding a single product only but that didn’t work either. The handles are different, so that’s not an issue.
Any help would be appreciated. Thanks :slightly_smiling_face: