Bad Customer Service

Went to Alma clinic on the 18 December service was great, requested invoice and i was sent POP, informed them that i wasn't sent the invoice they said they will send it to me, called so many times without assistance , called on the 28 Pumla said they are seeing an invoice for R312 and i told her i paid R320 so they need to fix that and send the invoice to me because its required at work, she said she would have to speak to the manager so that this would be changed and sent to me ASAP but unfortunately she never got back to me even after sending her 3 emails requesting for feed back . Today i called again a gentleman answered forgot his name and i requested the invoice , he said he will get back to me, i asked whats so hard in looking at the system and just emailing me the invoice while im on the phone he told me that he has other clients he needs to attend to before he can attend to me. I have been waiting for his feedback since 1 pm and still nothing. Im so disappointed with their service honestly because this has been dragging for so long and no one wants to assist.