That sucks :( should be easy to return in store at least
Arrived today, poor quality more like c grade large scratches on screen and back, getting returned tomorrow
I'm almost certain yours was carrier-branded, which usually takes ages to update - example here: https://community.o2.co.uk/t5/Android/Huawei-p9-nougat-update/td-p/1033120
Don't forget to do a backup if necessary before hard-resetting. My 'Plus' takes about a second to start up & be ready for a shot - is yours slower than that? The battery easily lasts the whole day, most days with medium-heavy use. It also has quick-charging capability & quick-charger which helps. I've had my Plus since Sept 2017 - bought 'as new', retail-boxed on eBay. The Plus model originally came out in April 2016, but no way to tell how old my particular handset really was, & even though it came with a Euro plug it didn't have a European firmware originally (I force-installed one later after unlocking the bootloader, etc). Also, did an online warranty check with the IMEI which came up with a vague message, but when I registered the phone with Huawei ID they gave me a year's free warranty. Mate 20 should be awesome, but expensive to begin with.
I previously got mine which was a Vodaphone P9 from CEX and it was unlocked to O2 no problem...fyi; https://www.ebay.co.uk/itm/142529961054