Because either (a) you never told the bank you are resident or (b) more likely, they're total idiots and never clicked on the box which says you're a resident when you gave them your change of address.
Some banks are even more collosally stupid than others, for example, they will change the status on your chequing account and send the statements to your Canadian address BUT, on your other accounts they never actually changed it. Really, really crap.
An NR4 is essentially the same as a T5, so when you do your tax return, you have to attach the NR4 to it in exactly the same way, and you use the gross amount to figure your tax. You cannot claim back the tax that was withheld anywhere on the T1.
You have to file an NR7-R with the NR4s and your T1 to get the tax back and God help you on that one, is all I can say. There is no electronic version of the NR7-R for EFILE so you have to use a paper return. If you file anywhere but to Ottawa, they will lose it in the internal post when it's sent to the non-resident dept. in Ottawa.
And the non-resident dept. in Ottawa doesn't follow their own instructions on their own form, they say you must file it with a T1, but the instructions say quite clearly you can file it separately with the NR4s at any point up to I think it's six years after you paid the tax to reclaim it.
I'm currently in the process of making a formal complaint to the CRA about that particular issue because the people in the non-resident dept. are utterly hopeless, to put it mildly. They have no e-mail address. They don't respond to faxes. They will not phone you. You have to do the whole thing by mail, although you can phone them or fax them, but they always respond by mail - maybe.
And in the meantime go to your bank and tell the morons in there to make sure ALL your accounts are set to resident, not just the chequing account.
There's a reason the
UK is the world's leading financial centre.
Steve.