Translation of invalidate in Spanish

We felt a little dumb and waited for the hot water. The boiler seemed not to work and we started to become upset. We asked the technician to come once again and he admitted his mistake.
Do you want learn Spanish? Do you have a telephone? I am looking forward to hearing from you and sorry again, I was extremely busy during the last three weeks. I hope you can forgive me.
We were a little sad that we had to leave Peru so soon, but we had to take the 7.30 bus which would take us to the Chilean border. Chile and Argentina were still the main destinations of our trip.