Tax credits online/phone discrepancy

[JLbaby]

I'm very new to tax credits and am finding them all very complicated. I've spoken to someone over the phone about what I may qualify for and also done the calculator, however both amounts have come up very different (from speaking to the person on the phone and doing it online) despite me giving them/entering the same details - am I missing something here?

Is there someone else I can speak to to find out exactly what I would qualify for?

I would phone Up the helpline and go with what they say. I have had trouble changing my single claim to a joint as online they told me I had to fill out a new form and they would send me one and it would would take 2 weeks and then after 2 weeks I didn't receive it and phoned them up only to be told they could have done it over the onions after all! So I'm still waiting to sort out a few issues but I would deffo phone them and go with what they tell your

Over the phone not onions haha

Problem is I've been told 3 different amounts over the phone too! And they vary massively, from £205per week, £173 every 4 weeks and £426 every 4 weeks!?

That's not good is it? They could at least be consistent! I have used a website called 'turn2us' which is a useful website to use for benefit entitlements too. I used the tax credit calculator too and it has told me I can get a certain amount and I'm just hoping it accurate !!