Hello Email issue. My "sent" folder has disappeared? Any Ideas? Mike

for weeks now I have wanted the email address on the account changed because my inbox is filling up with spam and phishing emails. Every time I contact them through the stupid WhatsApp all I get is "We have changed it" I look at the account they have...

my landline has a dialing tone but when I call it says it's ringing but it isn't. But it rang before the change over to wifi? Do I need a different phone it is a BT Phone.       [MOD EDIT: Subject title changed for clarity]