Cheri, Ray and Kerry are giving you excellent advice and I hope that you are able to calm down some after the initial panic. I bought my axolotls as an impulse buy, too, and kept them with goldfish and a catfish... Like I did, you are here now, learning, and so you are well on your way to being an informed axolotl keeper.
Ray, I just want to interject that dechlorinator is only necessary if the water has chloramines. If the water company treats the water with chlorine, chlorine will evaoprate. You can fill buckets with water from, say, a shower head to speed up evaporation, or you can let the water sit for a few minutes, hours, overnight. Chloramines do not evaporate, though, and a dechlorinator is necessary. In the US and Australia, water companies commonly use one or both chemicals to treat water and dechlorinators are indispensible; here in Germany, for example, they don't and we can take water right from the tap.
I don't know how it is in the UK so, Cheri, you can contact your local water company (either by phone or visit their website) to find out if they use chlorine/chloramines to treat your water. If they don't, you don't need a dechlorinator - one less expense and one less chemical in the water.
Lastly, just the tip that while your axolotl is in the fridge, you should have an extra bottle of (dechlorinated if nec.) water in the fridge with him so that when you do the water change, the fresh water has the same temperature as the water in the container.
Good luck to you,
-Eva