worse service ever

I made a payment on wed the 22nd and accidently paid the wrong amount as a settlement it hen contacted them and the person was helpful and said the matter will be resolved in 48 hours i was also given the difference in payment to be able to settle the account. since then its been a nightmare. 4 different people including a TEAMLEADER can see the payment but cant allocate the payment All i want is the account to be settled and to do business again with the company but the way things are going i am looking else where the name is fasta but this matter has been dragging for so long i am tired of sending the proof of payments logging tickets sending e mails even phoning all i get is the same old we will escalate we going to escalate i will be shocked if the matter is even sorted this year i mean if everyone can see the payment why is this so hard to do please just update my account and settle it finish en klaar