New Delhi: It was Micromax vs Xiaomi on retail websites on Tuesday, with both running successful flash sales of smartphones on e-commerce sites at the same time. In terms of customer satisfaction, Xiaomi buyers not only picked up more devices but also experienced hassle-free transactions. Micromax’s wholly-owned unit Yu Televentures, which introduced Yureka smartphones on Tuesday, offered and sold out 10,000 devices priced at Rs 8,999 each within three seconds on Amazon It was a frustrating experience for most of the 300,000 registered users who flocked to the sale as the site crashed, prompting some of them to vent their ire on Twitter . Xiaomi, which introduced flash sales on Flipkart back in July 2014, sold 50,000 of its Rs 9,999-priced Red Mi Note 4G – a direct rival to Yureka – two minutes and 50 seconds into the sale that started at 2 pm.Xiaomi has scaled up the number of devices offered on the website after it faced a massive consumer backlash when stocks were limited to 10,000 units in each of the first few sales.Top executives say they had greatly underestimated demand for the Mi 3, last year’s flagship device. Flipkart’s site had also crashed during Xiaomi’s first few online sales. The Chinese smartphone maker, which is ahead of Apple and Samsung in its home market, now puts on sale 100,000 units every week.On Tuesday, Xiaomi held two flash sales — the second one at 5 pm for the Red Mi 1S, priced at Rs 5,999, which was sold out within 11 seconds. Micromax’s spin-off phone brand, which uses CyanogenMod’s low-price operating system and an online retail-only model to take on Xiaomi, doesn’t seem to have learned from its competitor’s initial mistakes, watchers say.Some consumers expressed surprise over Amazon’s inability to handle the traffic surge, compared with Flipkart’s smooth experience while buying the Note 4G. “Very poor handling of Yu Yureka sale by @amazonIN had much better experience with Redmi Note sale,” said microblogger Ravi Gupta Some customers who didn’t manage to grab a Yureka smartphone claimed that the Amazon site crash may have been a gimmick. “Only god could have booked #youplaygod #Yureka through @amazonIN Its a shame that someone of @amazon scale cannot handle the load . Darn 503!” Sudheer Bhat , an unsuccessful buyer, said on Twitter. The Amazon India site showed a 503 error message for many users.