MRT train signal problem?

Last week, I went to work by taking MRT but was almost late during one of the weekdays. For that particular day, the MRT for some weird reason only stops at altenate stations meaning that some passengers who wants to alight at certain stations are denied the right to alight. Lucky for me though, the MRT managed to pull over at my station. Else, I may have to switch to the opposite side MRT to reach my station. I don't know how come this can happen especially during peak hours. This leads to some disgruntled passengers who laments about how poor the SMRT service is recently. I hope this is a one-off incident and not a routine one. Keeping my fingers crossed then. Lately, Ipad mini is released. According to the news, the response is not as good as previous launches. If thats the case, how come I cannot get hold of one during launch day then? Apparently, it is sold out within 3 hours of launch. So I wonder how good a response can be considered good especially it can be sold out so fast in Singapore? Challenger should have stock in more since there is a big demand for Ipad mini. So the next restock should have more Ipad minis for sale ya? It's anyone guess that it should be this way so that more customers can be satisfied. I know online ordering is another option but I rather wait for Challenger to stock in cos there is points to be earned if you are a member there. Hopefully it will not be too long a wait if not I may suddenly decides not to buy Ipad mini anymore.