im sorry your fish are getting sick and passing ....its so frustrating when we try our best and things go wrong..heres some suggestions I can give
1. get your own
test kit if you dont have one..that way you will ALWAYS know whats going on in your tank and you dont ever have to rely on others to tell you things are ok or not...
LFS are not always trustworthy...an
API liquid master test kit has everything you need and you can do hundreds of tests...its a must have IMO
2. once you have the kit, you will probably see that your cycle isnt completed because MOST meds kill the beneficial bacteria needed to keep the cycle going..so depending on your test results, will depend on your next move...
3. daily partial water changes with either prime or amquel + is whats needed to keep the fish safe and unstressed from a mini cycle
4. turning up the temp to 83-84F for two weeks, with extra airation as warmer water has less oxygen, and extra gravel vacs to get up the ich spores, usually will cure them...in etreme cases , meds will be needed....
5. ich is like the common cold to humans...the virus is always present around them but unless stressed or their immune system is down, they rarely show signs and dont get sick...so having a varied diet, cycled tank, and not over crowding, usually keeps ich away....
so getting your test kit and some prime or amquel + , would be what id suggest you do as soon as you can.....there is hope so dont give up!!!!!