i would maybe try to leave them alone completely until they have settled, spend lots of time in the room with them, but dont interact at all.. eventually they will get used to having you around, they may have been previously abused.
E.g. hit and repeatedly dropped..
Don't worry too much about them hiding, they are prey animals and it is their natural instinct to hide when in new surroundings.. let them get used to you, I used to read to my guinea pig to help him get used to my voice, and eventually he came to trust me and enjoy spending time with me!
As for not eating I would suggest you found somewhere good to hide and try to see if they come outside whn you are not there, be patient and monitor their food and Hay to see if it is decreasing, as
@nicky said before..
If not seek a vet's advice, as they may have problems with their teeth and / stomaches.
Guinea Pigs are extremely deceptive when it come to illnesses and injuries, they try t hide it, so be sure to have them checked out by a vet anyway, to make sure they are in good health..
Alot of guinea pigs do not eat in their first feww days i their new home, so be patient, and keep an eye on them, or even both eyes!
hope this helped
Feix the piggie's Mum