Hello, I need some help on FBA, I need viable solutions to this very specific problem

Ok so I’m new to Amazon FBA, I have not sold NOTHING AT ALL So I am at a capacity limit of 15 cubic foot So I can’t not request a capacity request because I am new Everything that I put on packing details and quantity to send it says “this product exceed your current FBA capacity limit for oversized storage. Expand capacity monitor at the bottom of the page to view maximum shipment volume for oversized storage” Everytime I modify or remove and start something new, I get the same exact problem I’m even talking to my supplier in alibaba, we did the math, we plugged in the numbers and the box that we are using DOES NOT EXCEED CAPACITY, which is 25x36x21 41lb I need help guys, I’ve been working on this Amazon seller account for 8 months, taking my checks reinvesting, moving blindly because the nuance stuff is always forget to mentioned, I got this far and I just need help, what do I do, I tried everything, even rounding the box dimension number’s off, smaller boxes, I want to buy another item, BUT I’m afraid of this happening all over again, I need solutions, solutions that WILL work guaranteed.