HAVE sentences – right or wrong?

Check out the following HAVE sentences. Some are right, some not. Can you correct the wrong ones?

1. I can see that my students HAVE a splendid time here in Malta.
2. Maria HAD BEEN HAVING her apartment for 10 years.
3. They‘RE HAVING serious problems with their accommodation.
4. We’VE BEEN HAVING too many late nights.
5. ARE you HAVING a public holiday on the 29th June in your country?