united mobile sms issue with tmobile USA

[b330i]

Hi,
I do not know if anyone is having the same issue as I do but I am not able to send/receive SMS to/from Tmobile cellphone users in USA... I called Tmobile USA and they mentioned that they have blocked Liechtenstein numbers... I need this to work because this is how I keep in touch while travelling; it just happens that the people that I need to keep in contact are Tmobile customers; so far I can SMS with Sprint users though..
I emailed UM customer service and at first they were very responsive (1 day reply) but now since I mentioned to them of this problem, they haven't replied to me for 4 days now.

Any Suggestions/Ideas??

Does anyone have any experience with mycherrymobile.com prepaid sim?? It looks promising (prices looks reasonable) and it has UK number but I do not know if it will have the same issues as united mobile... Although I would rather not buy another global sim cards... since they are not cheap.

Thank you in advance