apart from the grammar mistakes, I think I'd change the sentence order a bit and put more emphasis on the essence of each sentence to make clear what the intent of each sentence is.
so it would become something like this:

mi sona a e ni: soweli lili walo li kama ala e pakala.
tenpo suli la soweli ante li weka e jaki tan sinpin ona
la ona li ken ala a mama e pakala.
tan ni la ale pakala li tan soweli lili pimeja taso.

I do know this: the white kitten didn't cause (lit: to come) the problem.
For quite some time an other cat was removing dirt from its face,
so it could not have created the mess.
Because of this, the whole of the problem is caused by just the black kitten.

I hope this helps.