Box gutter replacement

I had them fit in a box gutter they sealed it on both sides with flashband I was sceptical as I checked it after, everything they seemed to seal with flash band even the gutter ends and it looked ugly I asked about it they were more in a rush to get done, things that were removed were not put back properly. The joint which sits in the middle they just fitted with no sealant. It rained a few days later, I had water running in my house, I phoned the owner Azeez he came to check it out told me he fixed it.. I had one last check to see what he has done, once again he put flash band on it.. It rained and leaked again.. I am waiting for him to fix it.. I have paid him quite a bit.. Overall he's unorganised, not always there to check if he's guys are working correctly, their workmanship is poor.. I would not recommend this business to anyone.