The best service provide by TNB

Yesterday I received my latest TNB bill

I was so surprise of the figure

Because normally my bill only cost about RM80-90

But this month archive to RM150

So I go and check my TNB meter

I found out they wrong written

My meter was 25603

But the bill was 25803

6 become 8

So today I call TNB ( 15454 )

They ask me to call KEDAI TENAGA ( 77843844 )

No body picks up the phone

They saying the line were busy

So I recall again

Then somebody pick up the phone

Then I told them regarding the bill problem

So they passed my line to another line (maybe technical department)

But I wait more than 15 minutes still nobody pick up the phone

So I recall again but I still need to wait 10 minutes

After that their provide a very good service

But my question is why I need to wait 15 + 10 minutes

What service is that?

What there are doing in that time?