Edward,

In my opinion, u shouldn't pay the RM 5K. How would u know that he will not ask u for another 5K again and again and tell u the same reason (rugi). Then u will have the same worry (kacau u, etc.) and it will back to the square again. Very difficult to come to an end.

Tell him that everything have to go as according to what been agreed earlier regardless of written or verbal. He cannot create a story just like that. Can i tell him now i got no money coz i rugi in business, etc and pay him less? How can he quote u a cheap price to get the business and charge u back later? Does it make sense? No need to let him know that he is the cheapest among other contractors u have compared.

Tell him that ur reno budget is very tight. And tell him that u have already spent RM 150K for the reno, over the years, for sure u will need to do some repair & maintenance and for sure u r going to give him more business. Tell him that u have some friends/families that are going to buy house and looking for contractor to renovate their house also and for sure u will recommend him to them. Give him the impression that u intend to work long term with him so don't spoil the relationship with the merely RM 5K. Ask him to just give and take. Tell him to be more professional and for long term, he is going to earn many many RM 5K. Tell him that u have some plan to do some extension for your house, etc but not now coz u need to save enough money first and he will get new business again. So come on lah, why u want to charge that RM 5K to spoil all this. Tell him those extra work is some good service that u expect from a good contractor.

But whether u will work long term with him or not or to give him business or not is another matter.