Since dev stores are for testing/dev they have a limited amount of orders that can be placed through them. Any limit you'd be seeing will be intentional.
If for some reason you need to increase your limit so you can run a few more tests, try talking to your partner manager. If you don't have a PM give the Shopify Support crew a shout to see if they can assist.
This is what my account and not a trial version: - https://livteknew.myshopify.com
When I check out I am getting the error message "
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