Wow you are SEVERELY overstocked for your tank size I'm afraid (125 liters = 33 gals). The two JD's alone would be overstocking. Just because they are small now doesn't really mean anything; bioload should be considered as well and apparently they're overwhelming your biofilter.
Also as you've been told they all will get very large (5-11"). Also the Bumblebees are Mbuna's and shouldn't be mixed with other species; also the bumblebees ideally should be in a group of 5 which you can't do.
I'm afraid your fish are going to have to be rehomed or returned. At 33 gals none of these fish are ideal for your tank size, even if you planned to upgrade it isn't going to work. Unfortunately the LFS dont' advise people correctly on stocking; it's always best to ask here first. You MAY be able to keep ONE of the fish you have currently, and that would just about fully stock your tank. I'm sorry you received poor advice.
You should also post this question with your tank size and stocking in the Cichlid forum; I'm only going by what I'm finding online but people with actual experience will be able to help you more.
Also daily 50-70% water changes (at least 1-2) to keep ammonia down and the water safe for fish is advisable until you decide what you need to do to stock the tank properly.
Sorry, I hope my reply isn't harsh. I could be totally wrong (I hope I am) but I do think you are overstocked for your tank size; whether you can ride out the ammonia spikes with water changes and hope the bacteria adjust to the higher load until you can upgrade tanks I really don't know. Again I'd recommend asking on the Cichlid forum as well. Good luck.