Patching brand new poorly done expansion joint sealant

I had a pool guy bid for sealing our pool deck expansion joints, and did the job poorly. There are gaps and cracks where the site was poured and directly under the diving board they didn’t meet the line of sealant. Other spots the sealant is literally just lying atop the sand gap filler, --it lifts off. It’s only 4 days old. I asked the guy to bring his sealant to patch these areas when he come to finish the job ( clean the DE filter only). *He said (without inspecting it) he can Not seal over sealant, & it was done properly.

To have him redo, can he just pour more sealant into cracks? Or cut out bad spots and reseal there? Or or must he reseal the entire thing because the sealant won’t adhere to itself and would allow minute water seepage?