So how exactly did ur khalu find out? when you were on the phone with ur khala and he walked in the house, you only spoke to him to find out his 'haal chaal' soo why would he be upset?
in case he is upset i think you should tell your parents about everything that has happened, most of the time they usually know how to handle these situations specially since its involving close relatives. your mom should have a talk to her sister about all the things shes doing. one thing is clear though, do not marry into this family because your khala is obviously very manipulative and will most likely stay that way.
so i say speak to your parents first and get their advice. if that somehow doesnt work then when u go there u should speak directly to ur khalu when u get there with ur father present as well.
lateron my khala told that her daughter does message me which sometimes my khalu also read when i replied in some cases and he previously had quarrelled about it becoz he is religious. but my khala has been doing all this secretly by hiding it from khalu
:(