Service is not bad.

Service is not bad.
But billing system and customer service are the worst.
I chat to solve a mistake as they over charged me.
The representative told me that he will escalate the issue and I should get a mail in 2 days.
Nothing happened.
Then I call the customer service a representative called Ella answered me after the second waiting time after having the verification she hold the line for 20 minutes.
10 days without solving me bill issue