you just need to stop spamming. Post natural answers maybe 10-20 answer daily related to your site. Don't force message people to your sites like "this is my site, go here" instead use a natural approach like Your Well written Answer then "This site may help for further understanding related to xxx"
It happened to me several times (every time). I think you should not insert links to answer body but you can insert links in resource box. Also if you post link ensure they are related. Unrelated link spamming is the main reason for Yahoo answer account suspension.
Depends on what they told you as the reason. I know they don't like it if someone just appears to be spamming to build back links.
I think you can't avoid the suspension. Because your goal is to put your url in the Yahoo answer. The readers community is very much critical. If you place your link on the appropriate answer they can consider it spam. If you won't provide any link & answer appropriately, then you can continue your account. In my opinion this is simply wastage of time.