Ok, here is my experience;
ezetop.com - I tried 4 times with PayPal but the payment wasn't accepted, and it was refunded back to me. My paypal account is a Malaysian one and verified using a VCC. Not sure what's the issue.
etopuponline.com - My 1st account gave an error because my name in etopuponline.com account didn't match with my name in PayPal account. Then I created a new account matching both account names (paypal and etopuponline) and it did work. But I received only 500 rupees for $5 recharge. Not good
lanka.info (Kapruka.com): It took few hours than other websites but now worked for both Dialog and Mobiltel without any issues. I'm paying using PayPal. I received 1160 rupees for $10 recharge. So it's the better option at the moment.