Translation - English-Romanian - I felt sorry that I couldn't ....

I felt sorry that I couldn't talk when you called me. I can write in Romanian by the help of computer. If you write me what you want to say, I can understand easily. If you receive a message from me, it is also enough to give a missed call as an answer. Then I will be able to understand that you have received my message. I don't want you to spend all of your units."