Just try one at a time the dialler can call you direct if you programme your number in phone number one as an example
Or just try the open tap details to send you an SMS via there site but leave your number out if that's what you want
I still think if you want just a general sms keep the dialler as a dialling unit and get another game unit to send the SMS it will be cheaper than open tap
There are some units that will dial and SMS and will choose depending on what is available ie if you had a line fail the SMS would send or vice versa
Don't make sense because it's not compulsory to have home insurance to have a supply of any kind
Therefore you are able to make a claim against anyone independently
If it doesn't work then open case , but I reckon your doing something wrong
Try doing it via https://www.open-telecom.co.uk/products-services/opentap-to-mobile-text-sms-and-email-messaging-gateway/
Expensive tho
Well then use the maintained tap service , but it's expensive not worth it for a general txt
Your better off using outputs and connecting to a gsm dialler and get a contract SIM that you don't have to top up, just have an SMS max
Then keep the phone dialer aswell