Sending Pictures as MMS/Email

Hi all

Im having a few problems sending pictures either as a MMS or even through emails. I can send regular emails and they deliver absolutely fine, but when I attach a picture in the email, it will keep trying to send the message but I won't ever get that tick by it.
When I try and send a MMS message, it will send but won't deliver. And today I tried sending myself a picture from my sister's phone and although I received the message, it read 'message cannot be retrieved at this time'...

Up until a week or two ago this wasn't a problem. I havent touched any settings so I cannot think of what it could be. I've tried doing a battery pull but it hasnt made a difference.

Can anyone suggest anything?

I have a Curve 8900 (Tmobile)

Thanks in advance