Kil is the root, which means to do.

Adding the suffix watisiz is what kiliwatisiz is doing.

Kiliwatisiz in the first sentence means, what are you doing?

The second sentence is a kind of idiom, which means to cancel the account, which is a special case.

In the usual continuous tense, the root of the verb is added with the suffix of the present continuous tense, such as ing in English and wat in Uyghur, but it is followed by a personal suffix, such as siz in the second person and siz=kilwatsiz in the root kil+ progressive aspect. ....