30th and 31st is working day, so low risk of missed

That is what I did and CS said ok but i need to make payment for outstanding transactions first and she will proceed to cancel my card, no offers at all. Haven't been using the card for the last six months except last week, could this be d reason?

Cons have RM 10 annual fee. But now having promo that annual fee will be waived for 1st year.
The 15% only apply to lazada transaction, I think shop back not eligible.

Do you mean buy from Lazada through Shopback? If yes, I can confirm can get the 15% cashback for CIMB Lazada prepaid card. Actually, you will get 16% cashback in total.

shopback is independent of which credit card you use

dude, 15% is from CIMB, so who charges to CIMB? Lazada, right? so you pay to lazada using CIMB card, then CIMB give you cashback accordingly.

for Shopback, does it linked to CIMB? do you even use CIMB card with Shopback? no right? Shopback only receive transaction from Lazada.

Shopback --> Lazada --> CIMB
hence, your question of "15% is not eligible for shopback" is an invalid question.