Increasing access amount

My son joined Budget Insurance in 2013 and was provided with a short term insurance contract for his vehicle. The contract state that his access when involved in a accident is R3 350.00. Now in June 2015 he was involved in an accident whereby a vehicle collided into his vehicle on the highway and caused R16 630.00 damage. When he lodged a claim Budget Insurance informed him that his access is now R9 600.00. Since 2013 his instalments increased and his access increased by 200%. How is that possible. He was not provided with a new contract at all and was at no stage informed that his access amount increased. I feel that Budget Insurance is not above board and is *********** their client.