You are looking for ecommerce internet marketing advice?
If you want to build a longer trust:
1)when you send them a product, have a personal note with possibly a coupon code
2)write them a personal thank you email if you have time to thank them and not some automatic thing
3)get a truste symbol or one that is very common online
4)have a 1-800 number above fold
I will leave more information as time goes on, but please leave some comments, bc these trust barriers will really help you out..
I have seen results from my ecommerce site and have had sales via phone because of the above fold 1-800 number