Login nightmare

Ever since i’ve had the app on my phone,i’ve always logged in by inputting 3 random numbers from my six digit pin.Lo and behold,over the last few days it has asked me for email and password,a timeconsuming process.After calling and live chat,no one could tell me why i couldn’t use a pin number.I uninstalled and reinstalled the app,logged in by email,went to login preferences,pin was highlighted but it didn’t work.As a last straw i enabled fingerprint login(rubbish on my phone,clicked change,change successful,then clicked pin and changed,this time it worked.No thanks for the lack of help from ID mobile,shame because i like everything else about them,just the lack of assistance.