Unless you let us know exactly what you said we can only guess which rule you may have contravened.
eBay has policies on what can and can't be said in feedback - but these are not all in the same place and can be hard to find.
Like many buyers, you generally leave one-line positive feedback, but can't resist telling the whole story when leaving negs. Unfortunately, the more you say, the more likely you are to say something that will entitle the seller to report it for removal.
We get so many questions about this since eBay removed the limit on the length of feedback comments. The irony is that a change intended to enable buyers to explain problems more fully has resulted in many having their feedbacks removed altogether.
