Wrong Platform plans

[Longtallkellie]

Hello, wise people. I am in desperate need of guidance...
We purchased our yurt from a family member, and they included the folder with the platform plans that the yurt originally came with, supposedly.
Long story, short- the platform schematics were for a different sized yurt. My poor husband, followed the directions to the letter, and got a platform that is 24’. Our yurt is 21’.
After the initial shock and outrage subsided, Kevin is extremely frustrated and assuming this is going to cost us tons of money to redo. Someone suggested just using L-brackets on top of the existing platform to connect the walls, which seems unstable to me, as there won’t be any tension to speak of.
We could really use some input on what our next steps should be, and any ideas on how to fix this problem without breaking our bank.
Thanks in advance!