Verb conjugation of "comprobar" in Spanish

The billing of additional working hours is not justified, since it was our request to download the software and wait for the new version. They have admitted the error of the translation.
Sometimes I visit Vocabulix to meet new people. It is true that one could do the same on Facebook, but the FB page is rather for friends, and you are less likely to contact strangers for this purpose.
If you want to write again in Spanish, just do it. I have much to do at the moment, again and again... Sometimes it happens that I must work at night until the early hours of the morning.