Could you please check these few sentences? Thank you

1) I've been a Tim subscriber for two years.
I top up my mobile every two weeks.
I recharge it every evening.
2) I keep in touch with my friends by sending them email and by chatting on Facebook.
3) I joined Facebook last summer.
I prefer sending email to texting my friends.

All are fine. =)

Certainly! I'd be happy to check your sentences.

1) I've been a Tim subscriber for two years.
I top up my mobile every two weeks.
I recharge it every evening.

These sentences are grammatically correct. However, there is one small change that could be made for clarity: "I recharge it every evening" would flow better as "I recharge my mobile every evening."

2) I keep in touch with my friends by sending them email and by chatting on Facebook.

This sentence is also grammatically correct. Nothing needs to be changed.

3) I joined Facebook last summer.
I prefer sending email to texting my friends.

These sentences are grammatically correct. However, to improve clarity, you could modify the second sentence to: "I prefer sending emails to texting my friends."

Great job with your sentences! If you have any more questions or need further assistance, feel free to ask.