Code, design and Woocommerce fixes in Wordpress website

I need a few fixes in my Wordpress website, respectively: - After the most recent update, Woocommerce's Paypal IPN isn't executing a function that was present previously. What it did is that it registered the user and sent him an email after payment, but now it's not being executed anymore. I have the function in php code, ready to be implemented - A button in the website's menu isn't being correctly shown in Firefox Windows 8.1 (might be wrongly shown in other browsers/OS as well) - When clicking on one of the categories of my blog, the posts get unformatted and occupy the whole page, overlapping with the right sidebar - I need to make a page and respective subpages, the child of another parent page, and change the links of all the Back and Next buttons This shouldn't be too hard to do, as in most it's just a quick fix. Please don't apply if you aren't a serious freelancer, I need this to be done quickly and without mistakes.