First time, he tightened the wrong belt. He didn't check all the belts from memory just checked one and tightened it and still had the same problem. Second time, he fixed "most" of the issue, he tightened the right belt but not enough it seems, it would only squeal for half a second maybe, then I went the third time and he said it was all good and he didn't want to tightened it anymore to not overtighten it.
Then it started getting worse again and it went back to squealing for around 5- 10 seconds or so. 4th time I went to a new mechanic who told me that my last mechanic didn't tighten it enough and he fixed it and I haven't had the problem since.