11% of $11,000 is $1210, so why did you contribute $2500 (almost 23%)?
The maximum SEP is roughly 18.5% of your business profit. So I have no idea why that person said 11%, as that seems completely random.
File an extension, and I *THINK* you can ask them to "remove excess contribution" (you can definitely do that today, before the April 15th due date, but I'm not quite sure if you can do that for a SEP after April 15th).
