first don't be sad,maybe the customer compared with other supplier,it seemed that as similar as yours,but the price is cheaper than you.so the customer ran away.
There are some reasons:
1,Maybe your this client just want to get free sample from you.When he get it,he will disappear,
2,For some reason,this project is pending on your client side.
3,Maybe your client is on his vacation.
4,Maybe he has resign or for some reason,he is not the key person who is in charge of this project.
....
Don't to be sad.Sadness can solove any problem.Be patience,and try to find some good reason,keep in touch with him.
Good luck to you and myself.