Business loan *** FNB

I lost my business because of Fnb, last year October I took a business loan +-R40k and my monthly installment was R1 650 per/m, I then paid for October but I was un able to pay for November and December, I then deposited 4k on the 22nd of January so they could deduct the outstanding arrears. Instead of deducting what I owed they blocked my account, I then received a payment of R18000 and they deducted it all and still my account remain frozen. I was never called or notified before they placed a hold on my account. I am now un able to invoice my costumer because my account is frozen, I tried complaining on there complain site but I was not even contacted.