Just sharing my experience. I decided to use the online renewal service this year. Completed the form, pressed the send button and had confirmation that it was received. Now, normally when I complete an online form and there is missing or incomplete information the system says "no" and highlights what's needed....it seems that tax credits forms are not that sophisticated (no surprise there with government systems - I am a former HRMC employee and know how bad their systems have always been). So I waited, and I waited, and I waited.........rang a couple of times and was told it could take up to 10 weeks. At no stage was I told there was a problem. Checked my account today in order to pay a bill......no tax credits. So rang at 08:00 this morning (took 45 mins to get through) to be told I hadn't completed the form correctly so TC's have stopped. I asked why they hadn't advised me of this, they don't, its up to me to check the form.....all I did was enter my self employed earnings AS THEY ASKED ME TO DO. All sorted now, but will have to wait up to 14 days for payments to resume. Just in case anyone else is in the same boat, or potentially in the same boat..........their system won't tell you if you haven't entered the correct info AND payments will stop. Moral to the story, doing it over the 'phone next year.