There aren't any grammatical mistakes, but I'll suggest a few changes: 1) to avoid repetition, change the second "tried" to "did." 2) we don't usually use "relay" with "situation." It sounds a little odd. I suggest saying, "explain the situation to you" or "notify you about the situation." The full sentence would be, "We tried to contact you about this and did our best to notify you about the situation."

I don't see anything wrong in there. As long as it's clear what "this" refers to, you should be good! Keep up the good work, Natalia.