Most of the time PAYPAL fails

First of all, I should thank you for this wonderful extension. Before a month ago, I was using Virtuemart which is heavy. So, I looked an alternate component in JED but nothing is better than yours. I'm using the free version in my live site. I like to move with the Business plan If the following issue is solved.

Issue :

I'm using Hikashop Paypal Plugin. The issue is that some users are able to pay successfully with the component and at the meantime some users can't. They complain me that the error code was 'Please try using a Valid Credit card(even if they try with the valid card)' or 'Please try using using a different payment method'. I have made the Address Override to No. Hope, you should have idea...Kindly help me!!!.

Dear Nocolas,

Thanks for your quick reply. But my doubt is, One of my client told that he is able to purchase some other products in online using the same credit card. Also, I haven't faced such an issue with Virtuemart but after I have changed to Hikashop, I've got three complaints in just 20 days which lead me to start this topic...

Thanks

Your extension is good and only issue is with Paypal payment system. I have also tried Tienda which is buggy but the Paypal payment system works fine in Tienda...

Thanks for your answer.

Let me contact Paypal in this case. If everything goes well, I will purchase the business plan:)

I have mailed to PayPal and still no reply. But, Today I faced a strange issue...

A Customer from Canada tried to purchase our product several times but couldn't get success. Just before, he mailed me that he moved to another company and purchased the same product using his same Paypal account...

I'm sure the issue is not with my PayPal account since some users can buy. Also, the issue is not related to country since the person can purchase in other sites...

Help me Pleaseeeeeeeeeeeee....