Occasional PayPal transactions not registering in our websites admin system - despite money being received ok!! -- 2

IMPORTANT: We will likely not be available to start work with you on this until Tuesday of next week when we have a full day available. But please bid as usual and we will accept one coder for the job. But please remember we will have limited time to input until Tuesday. Thank you! Our website is: [login to view URL] (custom php) Ok, so we both give free access, and also sell access to videos on our website. Here is an example of a video we sell access to: [login to view URL] When someone buys a video it takes them through to PayPal and they complete PayPal checkout, and then it returns back to our website with a thank you page, which then automatically redirects the user back to the video they purchased so they can watch it straight away. Now, the issue is when the user finishes PayPal checkout and it comes back to our website... We get around 1 in 5 (approx, it is random!) purchases that fails. The money is taken successfully by PayPal, but the sale is not registered on our admin system and so the user cannot view the video they paid for. This has caused us many issues (bad customer experience!) I asked the previous coder about this. He explained that this is happening because sometimes the transaction is reported back by PayPal as Complete, in which case everything works 100% ok... And sometimes the transaction is Pending, in which case the money is taken and the sale is not recorded in admin. Now, we're fairly certain we know why this is likely happening (but this is not 100% certain and needs further investigation!)... I believe that the Thank You page may be ending too early, i.e. not waiting until PayPal has given it's full confirmation that the payment is good. And so sometimes the transaction does not complete in time, as the Thank You page has an auto-redirect that takes the user to the video page after X number of seconds. The old coder I'm sure sourced the work out, so he does not understand it all 100% either, which does not help. But he could see most transactions reporting back as COMPLETE from PayPal, and the occasional one as PENDING (which would not show as a sale in our admin). However, the money was ALWAYS charged successfully with PayPal. So I do not think it is a PayPal issue, I think our website is either not allowing enough time, or otherwise our website is not waiting until the COMPLETE status is received before moving on (both are basically the same thing I guess!) So there needs some investigation and then behaviour adjustment so our website does not move forward before the COMPLETE status is successfully received from PayPal and details registered into our db (admin system).