API To Paypal - Social network

We run a social network dedicated to musicians and employers. There are 2 types of registrations, a free one for employers and a paid one for musicians. We have applied Paypal payment to all three subscription types, "one month" "six months" and "one year". Currently the subscriber's payment is collected and reoccurs at the designated interval. We need to automate the Paypal API to control the registration so that when a subscription is cancelled, the account becomes inaccessible until payment is made. Also at the end of the subscription cycle, the account becomes inaccessible until the subscription is renewed. The freelancer who takes this job on, has to be familiar and at ease with the following: Joomla, Jomsocial, PHP, MYSQL, Paypal API. Of-course work undertaken must be guaranteed against any future upgrades or Jomsocial and Joomla making sure that the code is not lost. Both Joomla and Jomsocial are "Open Source" anyway. We would need to discuss this job at length first before we allocate it to the "right" freelancer.