I will not try to not answer your question.
As you can see, double negatives can be confusing in any language, which is why it's best not to use them. However, sometimes these can help express what you are thinking, for example:
It's not that I don't want to go, but I have a conflicting appointment.
The double negative here helps emphasize that the decision to "not go" is by obligation, not by choice.
Side note: Abbreviations and colloquialisms like "u" for "you", or "wanna" for "want to" are OK for texts or email with your (young) peers. In general they are inappropriate for more formal communication with adults.
Proper spelling, proper capitalization, proper punctuation, and writing complete words and sentences are critical if you want to be taken seriously. It's a good idea to practice this wherever possible, and only use the more relaxed style with close friends.