... he mentions some parts (spacers? and springs?, sorry i don't know) he said the parts wear out and eventually the clearances no longer seal. ( i asked why they wouldn't have noticed that the 1st 2 times they did it but felt rude to push for answer, i'm sure they were trying to save me money and acting in good faith. )
I think it's ridiculous that you're asking for diagnostic advice on the internet when you should be asking the mechanic who is working on your bike.
Find out what parts the mechanic thinks you need. Tell them to fix the problem and stop wasting your time. They took your money, didn't they?