the problem is not the shop but with u.
First the liverock form the shop, might not be cured. by adding the rocks into ur new tank, u r just causing another ammonia spike. ur new tank...pls explain if u r using completely new water? some old water from ur old tank or alot of old water from ur old tank...
pls note that even when u add old water from ur old tank... and u top up wif new water...u r already changing the water chemistry... n shldnt intro new stuff into ur tank so quickly..
good luck