8ta / Telkom Mobile
8ta 3G network very bad durning 19:00 to 23:00

I buy a 60 60 package. but the network experience is very bad. I always use this card from 18:00-23:00.
I can see the signal is full with HSPA, but if you open any web, you must wait for 30sec or more, even if the web is local.
I try to feedback this to 8ta, but 8ta don't care about it. some people tell me that i must buy a boost. I am very confused that why? because I have good signal. I think that should be the core network have problem, because I ping any web, the time delay arrived to 500ms or 600ms. it is very slow.
my locaton is No.20 tamarack, home stead road, rivonia.
I feedback this issue some times. but no engineer come during night time.
if no body help me solve this issue, I will feedback this issue every week.