Can't deal with this level of incompetence!

Dealing with the VAF call centre has been an ABSOLUTE NIGHTMARE! I was not able to put down a deposit when I bought my vehicle in February. My situation has since changed and I contacted them in June to find out the process of making a deposit. Don't even bother to email them - they only respond 2 weeks to a month later, if you're lucky. When I didn't get feedback after 2 weeks, I phoned the call centre to get the necessary bank details & reference nr. I later received an email as well on my initial email request with the bank details & reference nr. As advised, I phoned them 3 days after making the deposit - only to find out that I "used the wrong reference number"... I received THREE different ref nrs from 3 different agents! I sent through my proof of payment - which they traced - and waited another week before phoning again. NOTHING has been done with my request to allocate the deposit to my principal debt. After 30min on the line I got cut off and sent an email to the agent with clear instructions. I also requested that my debit order be adjusted as I made the deposit well in time. It is now the 5th of the month and they haven't deducted my instalment. So I phone AGAIN. For some mysterious reason they decided they'll take the installment off my deposit. I AM FUMING!!!