My Janome dealer guarantees their cleaning for 180 days, if I'm not happy with how my machine works, "Just bring it back and we'll take care of it" is their motto. Most shops do not have in-house repairs, they send the machines out. I would definitely check with the dealer and see what they say. If they are a good dealer they will WANT to know that your machine was returned to you not properly cleaned. If their response is not good, go elsewhere and report back who the dealer was if you don't mind so others too can go elsewhere. And if your response is really terrible, I would suggest you contact Janome. Hope this all helps and Good Luck.