help with chemical #s

[summer time girl]

i need help,i had a company ruin my pool and come close to ruining 5 others pools.i go to court next week and no one can tell me from my analysis why my pool went bad.im going to give you all read outs that i have.first let me give u some history.they used gas chlorine,last may my pool started looking cloudy,milky ,july came and my pool looked like a pond.i fired them because they couldnt figure it out.huge and little black stains started rapidly spreading all over surface,i shocked it so many different times,with nol success,i finally had to take the pool down and acid washed it.the stains are still there,they are lighter in color from the acid wash,but it looks terrible.besides the black stains i had a yellow rough coating all over the surface..which has now ruined my walls,it is very rough. i ghuess those black stains are partly green in color.
heres some numbers
july11 /tot chlorine 10-free chlorine 10/ ph 6.9/ total alk 88/adj total alk 58
tot hardness 271
july 19 /total chlorine 4.3/free chlorine 3.8/ph 8/total alk 208/adjusted alk178/total hardness 347
august 7/total chlorine 10/free chlorine 10/ph 7.8/total alk 199/adjusted alk 154/total hardness 284.thats all the months that i have.remember the water started to look bad in may so i dont have 2 months of numbers..in the beginning myself and 5 others did have green algae growing in the corners of the stairs etc...
i need someone with the right knowledge to explain this to me.please take the time and help,i would so appreciate it...have a good day

[Pool Helper]

Seems the readings were all over the place. The ones I find disturbing are the massive changes in total alkalinity and pH.

I can't figure out why the total alk was bouncing around and being adjusted so often. The pH was probably a right mess too. In pools with high total alk fill water, I always keep pH at 7-7.2 to compensate for the higher carbonates.

The yellow coating is scale thanks to the high pH/ high TA combination.
The stains? Probably metals, maybe a contaminant from the chlorine gas or its container.