Website for booking Skype sessions (in Google Calendar) and paying online (bank card)

Hello there, I need a simple to use homepage for prepaid and free Skype services. 1) My clients should see available time slots from my Google Calendar and 2) could book and 3) pay single or regular sessions for a typically 3-6 months period. Booked sessions would 4) use some colour marks (categories) in Gcal and be marked as "busy", or if 5) cancelled: "free". My cancellation policy should be interpreted. I.e. 24 hrs cancellation is free of charge, and would set affected Gcal entries back as free. Late cancellation would also be set back as free but cost is TBD. 6) Repetitive absence without leave would result a cancellation with final calculations and removal of any booked sessions from Gcal. 7) Clients would pre-pay not all but some of the booked sessions at once online (typically 10 or 20 ). The Webpage should mark/note the last paid session and warn for billing the next 10-20 sessions. 8) A note should be generated upon payment with the paid/planned sessions. Billing is not necessary, I will copy and insert the said note manually into my invoice form. 9) The Website might offer other products (downloadable translated documents, thematised glossaries, other materials, printed cheat sheets, T-shirts and mugs with grammar rules, etc). 10) Ideally the webpage would be a standalone thing, i.e. NO third party (and/or paid) solutions apart from Google Calendar. Thanks for reading, feel free to ask/suggest (i.e. milestones). Please note, that UKRAINIAN Web developers/programmers are preferred. Slava Ukraine!