Leaving 17month old with 9 year old,sorry longgggg

[Cluesue]

Not sure I'm in the right place or should be in lone parents but here goes.
Exp has 17month old every Saturday from 3pm,returns by 8.30am Sunday,lots of history with trust issues,him lying etc.
Anyway my older dd(7)came home from school at end of term and said that a girl in her school had told her"your dad pays me £6 an hour to teach your sister on the tablet upstairs in pub while he's downstairs",I asked my daughter to repeat what she said.
I then phoned exp,(I admit I believed what I heard from my daughter,due to past issues with trust,lies,his drinking etc)I kept calm,no shouting,I explained what this girl had said to dd and asked him was it true,he said yes the girl was teaching dd2 but that she was teaching him too and he was there.
I said "ok,that's fine,but can you arrange for me to speak to the girl so she can verify exp is there at all times" "yes no problem" he said.
Fast forward a few days and I haven't heard off him so I text reminding him he said he would arrange for me to speak to the girl,no reply,5hours later i text to say if he cant be bothered to answer me,dont bother coming for dd the next day,he texts back"I've cancelled it now so no problem".
I reply that yes it is a problem,what went on before he cancelled it is the issue,He refused to discuss it any more to which I replied,if he wasn't arranging to clear this up then dd would not be going with him next day,standard reply,I'll see you in court along with f**king bitch etc.
My mum said I should have gone to the pub myself,but it's his local,he is good friends with the people who run it,works for them,parents of the girl etc.ive been I'll with PND and really cannot enter a hostile environment without prearrangement,and also I feel because he knows them,he set it up,it should be him that sorts it.
he withheld the DD's Christmas presents too
At no time have I stopped him coming to see dd,I have always been civil with him,would never cause atmosphere in front of kids.
I offered him to come here Christmas day,I offered to take DD's to his boxing day as previously arranged,he's said no to all,it'll get sorted in court,yet he's telling people I've stopped him seeing dd
So frustrated

It is not a very nice pub and the restaurant is probably very quiet in evenings too as not somewhere you would have to reserve or would think of going really,probably why it's been a pub grub,Indian and polish restaurant all in last 18 months, to be honest it wouldn't make a difference if it was the sweetest pub in Britain.
1, I don't believe he should be leaving her with a 9 year old
2,he has her for such a short period by choice, why can't he just spend the time with her,there is no need to be having someone teach her on a tablet

Did you ask him what the girl was actually supposed to be teaching your DD?

I've not had a tablet when mine were 17 months old and I can't imagine what you could 'teach' them on it.

Doing the drawing apps maybe, but you could do that with a pen/paper.

I have a 2.5 year old DD and she doesnt "learn" anything from the tab. She asks to watch Peppa Pig and will sometimes draw a picture on it. Your Ex is talking utter crap to justify spending his access time in the pub, access time which it seems to me he only insists on because he knows it pisses you off.

If you start acting like you dont care if he sees her or not and dont let him get to you, I rather suspect that the visits will soon tail off.