Dog was at a relatives house, ate table scraps and wont take her dog food anymore, HELP!?

My dog (3lb. chi) was at my relatives house while i was on vacation for 2 weeks, i come back and my relative says that my dog food is really bad, i buy wellness small breed and they feed their dogs IAMS, so i think they just dont know what theyre talking about and well... they dont they said the dog had been eating plenty of table scraps and would not take her food (i bought them a brand new bag of dog treats to avoid this [dogswell vitality chicken jerky] and they do it because they think the dog food isnt good for the her) -___-im naturally pissed and now i have my dog with me and she is not eating dog foodi put it down for half a hour, ive soaked it, ive put it in a kong, and hell ive even mixed in egg and chicken [which she started to pick at but i picked it up before she could just eat the egg and chicken]. im frustrated and idk what to do anymore , my dog had weight problems before [too thin] and now she is okay but i dont want her to fall into being this again because it really took alot to get her at her ideal weight. please help me!