MRT Circle Line @ Paya Lebar - No more train to Bishan, Harbourfront

I was at Paya Lebar station yesterday. Wanted to take train to Bishan.

But the service to Harbourfront has already been stopped for a few days. The notice at the waiting stated it clearly. (Forgot to take a picture.) Note: not disrupted, but terminated for good.

Tried to google official announcement from SMRT about this. Couldn't find anything.

What on earth is happening?:*:

I went to Paya Lebar Station again today. Here are the signs, showing the stopped service, with no indication of when service will be resumed, if ever.

(Please click on the image to see it clearly. Sorry, I couldn't get sammyboy to display the scaled-up images reliably.)
At Serangoon Station, there was train service to Bishan and Harbourfront. So it seems the breakage is at Paya Lebar Station.

Fig 1: No Service at this platform:


Fig 2: Signage about stoppage



Fig 3: Signage about stoppage, with road direction next to it

To see the images, need to log in. Sorry, will try to re-post when I have more time.