Trying to rejoin but thwarted

I had been with ID for two (?) years. However, I was seduced by tesco mobile family plan. However, that turned out to be a disaster as when I tried to port my number I lost all service. After a week of no data, no texts that worked, I tried to rejoin ID via carphonewarehouse to begin with and via the website when that didn’t work. 

In some ways the reason was laughable- my credit check was poor. I have a credit check score of 940/1000. Yes, go on, check yours!  The average for my area is 560 something. It really isn’t that. Is it because I left then wanted to rejoin quickly (two weeks)- do they think I am up to something rather than simply thinking Tesco is….emm, not very good (not the wording I really wanted to use). 

Should I simply pay as you go for 6 months then rejoin. Is there someone who I could actually talk to at ID? Options?

TIA