It's not actually great to have a limit so low.
Sometimes I wish(ed) I could (have been able to) transfer more than 100k per week and my limit on TheRock is even lower (3k per day), which is why I rarely use it.
I never changed my payment info and as far as I remember I only added USD-funds once in my SLifetime.
My 100k limit on VirWox also didn't change in years, I guess the only way to raise it is to contact them and beg for it.
There is nothing you can do besides contacting VirWox/TheRock if you don't pass the RiskAPI,
but if you don't pass today, it doesn't mean you won't pass tomorrow.
LindenLabs doesn't really give out any information about what kind of checkings they do, or what's required to pass the API, it's all supersecret (or in other words: LindenLabs sucks!).
Every day is different, all you can do if you fail to pass is try again the next day, sad but true.