Hi hope, I started a new thread on this topic which you should read regarding credit card fraud on these sites. All are legit sites, but the problem is with the credit card "payment gateway" that they (used?) to use. I see drugstore4save has changed theirs now (maybe that is what is different for you now?), but in the past I managed to receive an order from Drugstore4save only after using WesternUnion to get the money through, so you might want to try WesternUnion (you'll have to go to a physical Western uniion shop with cash as it won't work with WesternUnion online).
Other legit sites I have used:
Alldaychemist has an extensive range of antihelmintics (though has same credit card fraud problem, but is legit and will work with direct bank transfer). Based in India.
UnitedPharmacies (no problems with credit card here but read of others having problems in the past). Based in Hong Kong.
There are also some good Thai sellers on eBay.(e.g. search for "praziquantel 600" on ebay and you'll find the one I used.)