Converting air lines to a ticket on SIA website

I have 60,000 air miles. I wanted to convert it to a return ticket between Singapore and London.

I visited the Singapore Airlines website. I had a lot of trouble in locating the right page to view the number of air miles required for the different class of seats. After passing through this huddle, I keyed in the departure date, return date, and other details. The website said, "Sorry, we are not able to tell you. Please call our hotline".

I had to look for a hotline number. It was another challenging task. Finally I found it. The office was closed.

I called again today. I listened to the irrelevant announcements and finally managed to talk to someone.

SIA - Mr. Tan. Do you know that you can get the information online? You can a 15% discount when you make your booking online?
TKL - Yes. But your website refused to give me the number of miles required. They asked me to call your hotline.
SIA - OK. Please hold on

The staff gave me the required information. For one way, it is 59,000 on business class and 29,000 on economy. For return, it is two times of the air miles.

A while later, I called the hotline again. Another staff answered the call.

TKL - I want to know how many air miles are required for an air ticket on premium economy.
SIA - Hold on, Mr. Tan. I will check for you.

After a few minutes:
SIA - Mr Tan. It is 7,438 air miles on premium economy.
TKL - It can't be that low. I was told that it is 29,000 air miles on economy.
SIA - Mr. Tan, my calculator showed that it was 6,761 on economy. Let me check with my supervisor. I will call you back.

If SIA staff, who does this every day, can be confused with the website, how can they expect the poor customers to know how to get the information?

The process of converting air miles to a ticket is so complicated that, in the past years, I just let the air miles expire (good for SIA profit, but bad for customer's perception).