What payment terms did you give them and what payment terms did they agree to.
What was details on your written quote with regard to payment.
Did you have a works order number issued to you. did you rememember to put that on the invoice.
Normal payment from this sort of company is on 30 days, so you are jumping the gun a bit here, but some of these businesses will not pay until you chase it in.
No texts, no e-mails, phone calls only is the best bet, or if no too far from you arrange to call in and see them (nicely) it's amazing how quick some will pay if they know you are not too far away.