Bug fix! Good PHP coder for joomla project wanted

We have a joomla based project. Some coders tryed to solve the task, but they did't get it done. Mainly we have a working system. Users can choose and buy over a form a service. They get a invoice/voucher by email (created with a pdf-tool and a template). So far so good.... There are some little steps, that don't work, have a bug or are not implemented. Here is the list 1. when sending the voucher, there are 2 recipients needed, now we have three. One has to be removed. 2. we also get the voucher email twice, need to check the script for a bug. 3. We want to send in some cases automaticly invoices monthly. "at once" works, perfekt, but we need also the monthly feature. The admin must be able to turn the this autofeature for each user on/off. Maybe its a good idea to create/save the conditions on start of buying process to use them later for a cronejob(?). You are free to find a workable solution. 4. The voucher needs some extra fields needed to be displayed. The template is ready, so far. 5. The Invoices will be saved as "invoice_name".pdf, maybe ist better to change this to "invoice_locationID" and make the same to vocher = "voucher_location_ID" 6. because we want that all users can reach thier copys of invoice/vouchers on server by a simple list. 7. The voucher is small, but the PDF-file that will be created is A4. Maybe you change it to real size of voucher. Means, when the PDF is called by pdf-reader, it will open in the size of vocher, not in A4. The most things run over a file called "[login to view URL]" and are saved in our database, but you will need some time to figure it our how "the system" works. You need really good skills (PHP) to solve the task. !!! Don't bid if you can't start immediately. !!! You are welcome when you have really good knowledge !!! No payments if the job is not done. !!! You have to work online on server. !!! We have a budget of 250$ for this task. !!! The job has to be done in 7-8 days.