You can ask about the job scope if you might wan to know in details. Also can ask about the career advancement.

-Customer Service is a stressful job, can you handle the stress???
Every job comes with stress. I would prefer to deal with the stress by reacting on it than to stress about it. This way I can handle the situations better. Working under pressure is somewhat motivating to me too as it makes the job more challenging.

-Can you handle people scolding you on a daily basis?
I believe that nobody likes to be scolded, more so on a daily basis. If I am being scolded (for valid reasons) that could mean that I am not doing my job properly and I will find ways to improve.

-How would you handle an unsatisfied customer???
I would first need to calm the customer down and if necessary, to isolate the customer. I will then try to find out the problem that the customer encountered and then find ways to solve it. If time is needed, I will keep he customer updated on the progress and inform them on the solution once done. I will make sure that I own the complain and follow through with it.

The above is just my 2 cents. Hope it helps. 

As long as u understand the meaning then use ur own words will be easier for u. But definitely have to stay calm, else u'll fail the interview or come across as not confident. 

From what I know, yes they do.

I hope you don't take this the wrong way, but brush up on your grammar. Perhaps English is not your common language, but it carries a lot of weight during interviews and bad grammar do affect your chances.

Secondly, have a list of keywords for the 'common' interview questions and keep practicing in answering those using the keywords, so you won't forget what you wanted to say (keywords are easier to remember than whole phrases) and you won't sound too rehearsed when saying it.

I'm not sure what advice I can give, but don't focus on being perfect for the job, focus on being comfortable with yourself and your capabilities to take on the job.

It's a standard line, usually they mean your payslip, offer letter etc of your previous company but if you are a fresh graduate,  just take along your academic documents.

Haha, you are allowed to show your own payslip. Whether you want to or not is another set of questions.

I guess feeling nervous during interviews is a norm. I always tell myself to treat them as 'a new fren'. Dat way, I'll not be so tensed. All the best to you ya!
I worked for a company for 4 years, underpaid too. With the yearly increment, I was still underpaid in the market for that managerial role but I took it as a learning journey for me to climb up the career ladder. 
Is that ur first baby? If so, I guess it's fine to tell them that you were focused on the pregnancy during that time. However, some might take it as that you were unable to handle both working and pregnancy at the same time and you might lose scores here.

Nope, you won't get into trouble. It is private and confidential to the people you choose to show to, but you are within the means to show it. I'm not sure if letting your current employer know you are actively seeking another job is a good idea, but you can certainly offer that option.

Will it lower you chances? It is difficult to say. I'm tempted to say no, because of my personal experiences but I can't say that it won't lower it. Some people will view it as a negative point, some will not view it as something negative. You just have to convince them why you are not comfortable in sharing your payslip and hope they see reason to it.