Hi,3 months ago i cleaned a Spanish tile for a customer,kitchen and dining room floor.I was there to clean there carpets and told them i would clean them but as i have no training in hard floor as yet is was up to them.They cleaned up fine,now they wanted them sealed but did not want to pay me to do it and asked could i get them some sealer as they could do it them selfsSo i got them prochem sealer and left them to it.Lady calls today and says the floors water marking when anything drops on it.Now.she not saying anything to say its my fault but i would like to rectify the problem,any advice,thanks..