ally80,
50% of 3k = 1.5k, and your friend needs to rely on you to do the running. Any special relationship between you two? Like mother and son, spouses? Coz Girlfriend Boyfriend wouldn't work here.

Usually everyone would want to speak DIRECTLY to that person that lost the card for verification and deals. Are you going to do on his behalf? Writing letter, talking on phone?

If both of you same gender, that will be great because I would suggest you to ACT on his behalf, by being HIM. Memorize his details like IC, Address, Maiden Name and so on for verification and take full authority and responsibility as though I am the one lost the card (even it was at his fault).

But then, the above is bullsh*t. Because you are a female nick, so i can safely presume you are a girl. And girl is easily getting bullied through the phone if you don't have the commanding voice (imagine how a police questions thief, lawyer talks with stern voice, or the time you quarrel with people to show you MEAN BUSINESS). So you better brush up your tone in the phone Drian and Hansel said. I agree with them.

And normally when dealing with civil servants, it's best you talk to MORE of them. Some tend to be lazy and give simple answer. Jot down their name. Avoid talking further to the one that isn't favorable in helping you out. You can sense it through the conversation.

Writing letter is time consuming so if you do that, be prepared to have some ready up answers to counter the bank. They usually will pressure you to pay up in quickest time, so reinforcement would never come in time. Tell them you have sent letters to so-and-so and is waiting for their reply I WILL TAKE ACTIONS ONLY AS ADVISED BY SO-AND-SO. Make sure you really do write and send the letter.

Going to court, look arguably favorable in your position if you have called the bank service center and lodged the police report ASAP. I not certain on the RM250 max liability, but if I do i will go for it if it exceed 5k of transaction. Because, saving yourself that 1.5k might land you a heavier price on the lawyer fee. You need to take leave to attend court, and another for the verdict. Time, petrol and energy spent there could be well invested in other more rewarding activities. There is also a small chance that you might lose and then you will have to bear the court fee, penalty fee and ALSO the lawyer fee again! Small, yet it is still a risk. You will never know what witness from BNM that the opposition lawyer will bring to the court, and that might be the same lazy worker that told you "..just a guideline..mean no need follow one.."
You will run amok in court that time.

Then you lose the case, you will be lucky if you are spared from being blamed or busybody.
Court fee + Lawyer fee + Bank interest and dividend = would be higher than your credit card 3k by then.

But if you win, congratz - you saved 1.150k (minus that rm250 max liability).

So I just want you to know that,
Have You Seriously Weighted Your Option?
The good, bad, the effort required, the risk of losing, its consequences...

Don't do it because everyone telling you that you SURELY can WIN IT,
or because YOU FEEL EMOTIONALLY EFFECTED by the issue.
RIGHTEOUS? Helping a person?

Is it worth it to do all this

Your choice.

I already made my conclusion if I am you, but I won't tell you.