Just been to the Ministry of Labour at Chiang Mai's city hall with my wife in tow. They told us that we should be paid as stated in the contract but can't take any action until they dont pay me at the end of April. Hopefully a few polite words to my boss telling him what they said should do the trick.
If they don't pay me I will get a lawyer and they should get my final pay-cheque. Hopefully being diplomatic though will save everyone a lot of hassle.