Query on Sales agreement regarding Civil Works

I have a supplier who has explicitly mentioned civil works as part of the customer scope for the construction and installation of machinery for an aquaculture unit. I assumed civil works only referred to construction and excluded welders. However, he requested the welders, and we supplied the welder under the assumption that he would pay for him. However, he claims that civil works includes the welder. In agreement, he mentioned the plumbers and electricians needed for construction but not the welders. As a result, I'd like to know if the civil works include welders as required by law. If you want to contact me, please keep in mind that the number listed below can only accept WhatsApp calls.