In Yahoo mail when you have junk emails you should be able to go over to the "more" tab and select block sender from the drop down list and permanently block the offending sender. If it's the same ones sending stuff this should thin them down if they are from constantly changing addresses you need to keep blocking them.

Unfortunately if your address is on a spamming list it seems they keep pouring in and in but you can set it up to sort into a spam folder them delete and block them all.

Hotmail /Outlook Live has this feature too.

I download emails on computer using Thunderbird. This allows me to set up my own filters and folders to sort stuff as it comes in . Spam, stuff I want like ads and coupons and sales, regular inbox, specialized folders from different people or group communications etc. 

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