I note from looking at your account that you have been an eBay user since Friday 27th June 2008, but when did you first register as a seller on eBay? If this was done recently did you sign up to eBay's Managed Payments? If so then you should have received a micropayment from eBay into your account to confirm that they had the correct account details to pay into. Before you do anything else check to see if this has been carried out correctly, as if you either made a mistake at this stage, or didn't do it at all, then that would explain why you have not received your payment yet. However, eBay do retain money from new sellers for a longer period of time than they do with established sellers, and you need to ensure that you send your items via a tracked service so as to ensure that your funds are released to you sooner once the tracking updates and confirms successful delivery of the item to the buyer.
In the event that you have already registered for eBay Managed Payments and have provided all of the other information that eBay requested of you, then if your account keeps on asking you to add your details again then it may be possible that there is a glitch somewhere which is affecting things. If you think that this may be the case then it might be worth contacting eBay Customer Services in order to discuss the problem with them to see if they can resolve the matter with you. In order to contact them click on the following link https://www.ebay.co.uk/help/eua?id=5275&mkevt=1&mkpid and a new page will appear on the screen. Scroll right down to the bottom of the page, click on the blue button that says "Have Us Call You" and you should receive a phone call from an eBay representative shortly afterwards. However, it is often better to request a call when eBay's lines first open, as that way you have a far greater chance of receiving a phone call from one of eBay's far more knowledgeable representatives based in Dublin, as if you leave it until the afternoon or evening you are more likely to receive a phone call from an eBay representative working out of eBay's Philippines-based call centre, in which case you may possibly end up dealing with somebody whose English is not as fluent as it should be, which could potentially lead to further confusion. The lines open at 8:00am from Monday to Friday and close at 10:00pm, whereas on Saturday and Sunday the lines open at 9:00am and close at 6:00pm.
