The call is not hard because you do not know what to say. It is hard because making it requires holding several things at once: why you are calling, what outcome you want, the two facts you must not forget, and the ability to think while a stranger talks at you.
That is a working memory problem, not a motivation problem, which is why telling yourself to just do it has not worked for three weeks.
What helps is taking those things out of your head and putting them somewhere you can see them, so the call only requires the part you can actually do.
Five minutes before you dial
Write these down. On paper, on a screen, anywhere you can see them while talking.
5 things to do
Ticks are for this visit only. Nothing here is saved anywhere.
Write the first sentence out
The first fifteen seconds are the part almost everybody rehearses and dreads, and they are also the part you can prepare completely. Once you are through them, the conversation usually carries itself.
Something as plain as this works: hello, I have a problem with my account and I am hoping you can help me sort it out. Can I explain what has happened. You are not performing. You are getting past the opening.
While you are on the call
Short, because anything longer is unreadable while somebody is speaking to you.
- Say what you need.
- Ask them to read the details back once they have found it.
- Ask what happens next, and by when.
- Get a reference for the call, and the name of who you spoke to.
If you get through it and nothing is resolved
That is a normal outcome and not a failed call. Plenty of calls end with somebody else needing to look into it. What matters is that you now have a reference and a name, which means the next call starts from where this one stopped rather than from the beginning.
If you do not manage it today
Then you do not manage it today. Nothing has got worse, and adding guilt to the pile has never once made the next attempt easier.
The thing worth protecting is that the preparation you did is still there tomorrow. Starting over from nothing is what makes the second attempt harder than the first, and it is entirely avoidable.